Publications

Year 2019


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Grechuta, Klaudia, De La Torre, Javier, Rubio, Belé, Verschure, P., (2019). Challenging the boundaries of the physical self: purely distal cues in the environment impact body ownership bioRxiv , 672139

The unique ability to identify one’s own body and experience it as one’s own is fundamental in goal-oriented behavior and survival. However, the mechanisms underlying the so-called body ownership are yet not fully understood. The plasticity of body ownership has been studied using two experimental methods or their variations. Specifically, the Rubber Hand Illusion (RHI), where the tactile stimuli are externally generated, or the moving RHI which implies self-initiated movements. Grounded in these paradigms, evidence has demonstrated that body ownership is a product of bottom-up reception of self- and externally-generated multisensory information and top-down comparison between the predicted and the actual sensory stimuli. Crucially, provided the design of the current paradigms, where one of the manipulated cues always involves the processing of a proximal modality sensing the body or its surface (e.g., touch), the contribution of sensory signals which pertain to the environment remain elusive. Here we propose that, as any robust percept, body ownership depends on the integration and prediction of all the sensory stimuli, and therefore it will depend on the consistency of purely distal sensory signals pertaining to the environment. To test our hypothesis, we create an embodied goal-oriented task and manipulate the predictability of the surrounding environment by changing the congruency of purely distal multisensory cues while preserving bodily and action-driven signals entirely predictable. Our results empirically reveal that the way we represent our body is contingent upon all the sensory stimuli including purely distal and action-independent signals which pertain to the environment.


Freire, I. T., Arsiwalla, Xerxes, Puigbò, J. Y., Verschure, P., (2019). Modeling theory of mind in multi-agent games using adaptive feedback control ARXIV Computer Science, (Multiagent Systems), 1-30

A major challenge in cognitive science and AI has been to understand how autonomous agents might acquire and predict behavioral and mental states of other agents in the course of complex social interactions. How does such an agent model the goals, beliefs, and actions of other agents it interacts with? What are the computational principles to model a Theory of Mind (ToM)? Deep learning approaches to address these questions fall short of a better understanding of the problem. In part, this is due to the black-box nature of deep networks, wherein computational mechanisms of ToM are not readily revealed. Here, we consider alternative hypotheses seeking to model how the brain might realize a ToM. In particular, we propose embodied and situated agent models based on distributed adaptive control theory to predict actions of other agents in five different game theoretic tasks (Harmony Game, Hawk-Dove, Stag-Hunt, Prisoner's Dilemma and Battle of the Exes). Our multi-layer control models implement top-down predictions from adaptive to reactive layers of control and bottom-up error feedback from reactive to adaptive layers. We test cooperative and competitive strategies among seven different agent models (cooperative, greedy, tit-for-tat, reinforcement-based, rational, predictive and other's-model agents). We show that, compared to pure reinforcement-based strategies, probabilistic learning agents modeled on rational, predictive and other's-model phenotypes perform better in game-theoretic metrics across tasks. Our autonomous multi-agent models capture systems-level processes underlying a ToM and highlight architectural principles of ToM from a control-theoretic perspective.


Santos-Pata, Diogo, Zucca, Riccardo, Lopez Carral, Hector, Verschure, P., (2019). A simplified spiking model of grid-cell scale and intrinsic frequencies bioRxiv , 544882

The hexagonal tessellation pattern of grid cells scales up progressively along the dorsal-to-ventral axis of the medial entorhinal cortex (MEC) layer II. This scaling gradient has been hypothesized to originate either from inter-population synaptic dynamics as postulated by attractor networks, from projected theta frequencies to different axis levels, as in oscillatory models, or from cellular dynamics dependent on hyperpolarization-activated cation currents. To test the hypothesis that intrinsic cellular properties account for the scale gradient as well as the different oscillatory frequencies observed along the dorsal-to-ventral axis, we have modeled and analyzed data from a population of grid cells simulated with spiking neurons interacting through low-dimensional attractor dynamics. To investigate the causal relationship between oscillatory frequencies and grid-scale increase, we analyzed the dominant frequencies of the membrane potential for cells with distinct after-spike dynamics. We observed that the intrinsic neuronal membrane properties of simulated cells could induce an increase of grid-scale when modulated by after-spike reset values. Differences in the membrane potential oscillatory frequency were observed along the simulated dorsal-to-ventral axis, suggesting that, rather than driving to the increase of grid-scale as proposed by interference models of grid cells, they are the result of intrinsic cellular properties of neurons at each axis level. Overall, our results suggest that the after-spike dynamics of cation currents may play a major role in determining the grid cells scale and that oscillatory frequencies are a consequence of intrinsic cellular properties that are specific to different levels of the dorsal-to-ventral axis in the MEC layer II.


Pérez-González, Carlos, Alert, Ricard, Blanch-Mercader, Carles, Gómez-González, Manuel, Kolodziej, Tomasz, Bazellieres, Elsa, Casademunt, Jaume, Trepat, Xavier, (2019). Active wetting of epithelial tissues Nature Physics 15, 79-88

Development, regeneration and cancer involve drastic transitions in tissue morphology. In analogy with the behaviour of inert fluids, some of these transitions have been interpreted as wetting transitions. The validity and scope of this analogy are unclear, however, because the active cellular forces that drive tissue wetting have been neither measured nor theoretically accounted for. Here we show that the transition between two-dimensional epithelial monolayers and three-dimensional spheroidal aggregates can be understood as an active wetting transition whose physics differs fundamentally from that of passive wetting phenomena. By combining an active polar fluid model with measurements of physical forces as a function of tissue size, contractility, cell–cell and cell–substrate adhesion, and substrate stiffness, we show that the wetting transition results from the competition between traction forces and contractile intercellular stresses. This competition defines a new intrinsic length scale that gives rise to a critical size for the wetting transition in tissues, a striking feature that has no counterpart in classical wetting. Finally, we show that active shape fluctuations are dynamically amplified during tissue dewetting. Overall, we conclude that tissue spreading constitutes a prominent example of active wetting—a novel physical scenario that may explain morphological transitions during tissue morphogenesis and tumour progression.


Schierwagen, Robert, Alvarez-Silva, Camila, Madsen, Mette Simone Aae, Kolbe, Carl Christian, Meyer, Carsten, Thomas, Daniel, Uschner, Frank Erhard, Magdaleno, Fernando, Jansen, Christian, Pohlmann, Alessandra, Praktiknjo, Michael, Hischebeth, Gunnar T., Molitor, Ernst, Latz, Eicke, Lelouvier, Benjamin, Trebicka, Jonel, Arumugam, Manimozhiyan, (2019). Circulating microbiome in blood of different circulatory compartments Gut 68, (3), 578-580

Pose, Elisa, Trebicka, Jonel, Mookerjee, Rajeshwar P., Angeli, Paolo, Ginès, Pere, (2019). Statins: Old drugs as new therapy for liver diseases? Journal of Hepatology 70, (1), 194-202

In addition to lowering cholesterol levels, statins have pleiotropic effects, particularly anti-inflammatory, antiangiogenic, and antifibrotic, that may be beneficial in some chronic inflammatory conditions. Statins have only recently been investigated as a potential treatment option in chronic liver diseases because of concerns related to their safety in patients with impaired liver function. A number of experimental studies in animal models of liver diseases have shown that statins decrease hepatic inflammation, fibrogenesis and portal pressure. In addition, retrospective cohort studies in large populations of patients with cirrhosis and pre-cirrhotic conditions have shown that treatment with statins, with the purpose of decreasing high cholesterol levels, was associated with a reduced risk of disease progression, hepatic decompensation, hepatocellular carcinoma development, and death. These beneficial effects persisted after adjustment for disease severity and other potential confounders. Finally, a few randomised controlled trials have shown that treatment with simvastatin decreases portal pressure (two studies) and mortality (one study). Statin treatment was generally well tolerated but a few patients developed severe side effects, particularly rhabdomyolysis. Despite these promising beneficial effects, further randomised controlled trials in large series of patients with hard clinical endpoints should be performed before statins can be recommended for use in clinical practice.


Horteläo, Ana C., Carrascosa, Rafael, Murillo-Cremaes, Nerea, Patiño, Tania, Sánchez, Samuel, (2019). Targeting 3D bladder cancer spheroids with urease-powered nanomotors ACS Nano 13, (1), 429-439

Cancer is one of the main causes of death around the world, lacking efficient clinical treatments that generally present severe side effects. In recent years, various nanosystems have been explored to specifically target tumor tissues, enhancing the efficacy of cancer treatment and minimizing the side effects. In particular, bladder cancer is the ninth most common cancer worldwide and presents a high survival rate but serious recurrence levels, demanding an improvement in the existent therapies. Here, we present urease-powered nanomotors based on mesoporous silica nanoparticles that contain both polyethylene glycol and anti-FGFR3 antibody on their outer surface to target bladder cancer cells in the form of 3D spheroids. The autonomous motion is promoted by urea, which acts as fuel and is inherently present at high concentrations in the bladder. Antibody-modified nanomotors were able to swim in both simulated and real urine, showing a substrate-dependent enhanced diffusion. The internalization efficiency of the antibody-modified nanomotors into the spheroids in the presence of urea was significantly higher compared with antibody-modified passive particles or bare nanomotors. Furthermore, targeted nanomotors resulted in a higher suppression of spheroid proliferation compared with bare nanomotors, which could arise from the local ammonia production and the therapeutic effect of anti-FGFR3. These results hold significant potential for the development of improved targeted cancer therapy and diagnostics using biocompatible nanomotors.

Keywords: 3D cell culture, Bladder cancer, Enzymatic catalysis, Nanomachines, Nanomotors, Self-propulsion, Targeting


Patino, Tania, Porchetta, Alessandro, Jannasch, Anita, Lladó, Anna, Stumpp, Tom, Schäffer, Erik, Ricci, Francesco, Sánchez, Samuel, (2019). Self-sensing enzyme-powered micromotors equipped with pH-responsive DNA nanoswitches Nano Letters 19, (6), 3440-3447

Biocatalytic micro- and nanomotors have emerged as a new class of active matter self-propelled through enzymatic reactions. The incorporation of functional nanotools could enable the rational design of multifunctional micromotors for simultaneous real-time monitoring of their environment and activity. Herein, we report the combination of DNA nanotechnology and urease-powered micromotors as multifunctional tools able to swim, simultaneously sense the pH of their surrounding environment, and monitor their intrinsic activity. With this purpose, a FRET-labeled triplex DNA nanoswitch for pH sensing was immobilized onto the surface of mesoporous silica-based micromotors. During self-propulsion, urea decomposition and the subsequent release of ammonia led to a fast pH increase, which was detected by real-time monitoring of the FRET efficiency through confocal laser scanning microscopy at different time points (i.e., 30 s, 2 and 10 min). Furthermore, the analysis of speed, enzymatic activity, and propulsive force displayed a similar exponential decay, matching the trend observed for the FRET efficiency. These results illustrate the potential of using specific DNA nanoswitches not only for sensing the micromotors’ surrounding microenvironment but also as an indicator of the micromotor activity status, which may aid to the understanding of their performance in different media and in different applications.

Keywords: Micromotors, DNA-nanoswitch, pH detection, Self-propulsion, Nanosensors, Nanomotors


Wang, Lei, Hortelão, Ana C., Huang, Xin, Sánchez, Samuel, (2019). Lipase-powered mesoporous silica nanomotors for triglyceride degradation Angewandte Chemie International Edition 58, (24), 7992-7996

We report lipase-based nanomotors that are capable of enhanced Brownian motion over long periods of time in triglyceride solution and of degrading triglyceride droplets that mimic “blood lipids”. We achieved about 40 min of enhanced diffusion of lipase-modified mesoporous silica nanoparticles (MSNPs) through a biocatalytic reaction between lipase and its corresponding water-soluble oil substrate (triacetin) as fuel, which resulted in an enhanced diffusion coefficient (ca. 50 % increase) at low triacetin concentration (<10 mm). Lipase not only serves as the power engine but also as a highly efficient cleaner for the triglyceride droplets (e.g., tributyrin) in PBS solution, which could yield potential biomedical applications, for example, for dealing with diseases related to the accumulation of triglycerides, or for environmental remediation, for example, for the degradation of oil spills.

Keywords: Enzyme nanomotors, Lipase, Micromotors, Oil removal, Self-propulsion


Pacheco Estefan, D., Sánchez-Fibla, M., Duff, A., Principe, A., Rocamora, R., Zhang, H., Axmacher, N., Verschure, P., (2019). Coordinated representational reinstatement in the human hippocampus and lateral temporal cortex during episodic memory retrieval Nature Communications 10, (1), 2255

Theoretical models of episodic memory have proposed that retrieval depends on interactions between the hippocampus and neocortex, where hippocampal reinstatement of item-context associations drives neocortical reinstatement of item information. Here, we simultaneously recorded intracranial EEG from hippocampus and lateral temporal cortex (LTC) of epilepsy patients who performed a virtual reality spatial navigation task. We extracted stimulus-specific representations of both item and item-context associations from the time-frequency patterns of activity in hippocampus and LTC. Our results revealed a double dissociation of representational reinstatement across time and space: an early reinstatement of item-context associations in hippocampus preceded a later reinstatement of item information in LTC. Importantly, reinstatement levels in hippocampus and LTC were correlated across trials, and the quality of LTC reinstatement was predicted by the magnitude of phase synchronization between hippocampus and LTC. These findings confirm that episodic memory retrieval in humans relies on coordinated representational interactions within a hippocampal-neocortical network.


Arqué, Xavier, Romero-Rivera, Adrian, Feixas, Ferran, Patiño, Tania, Osuna, Sílvia, Sánchez, Samuel, (2019). Intrinsic enzymatic properties modulate the self-propulsion of micromotors Nature Communications 10, (1), 2826

Bio-catalytic micro- and nanomotors self-propel by the enzymatic conversion of substrates into products. Despite the advances in the field, the fundamental aspects underlying enzyme-powered self-propulsion have rarely been studied. In this work, we select four enzymes (urease, acetylcholinesterase, glucose oxidase, and aldolase) to be attached on silica microcapsules and study how their turnover number and conformational dynamics affect the self-propulsion, combining both an experimental and molecular dynamics simulations approach. Urease and acetylcholinesterase, the enzymes with higher catalytic rates, are the only enzymes capable of producing active motion. Molecular dynamics simulations reveal that urease and acetylcholinesterase display the highest degree of flexibility near the active site, which could play a role on the catalytic process. We experimentally assess this hypothesis for urease micromotors through competitive inhibition (acetohydroxamic acid) and increasing enzyme rigidity (β-mercaptoethanol). We conclude that the conformational changes are a precondition of urease catalysis, which is essential to generate self-propulsion.

Keywords: Biocatalysis, Immobilized enzymes, Molecular machines and motors


Cabré, Gisela, Garrido-Charles, Aida, Moreno, Miquel, Bosch, Miquel, Porta-de-la-Riva, Montserrat, Krieg, Michael, Gascón-Moya, Marta, Camarero, Núria, Gelabert, Ricard, Lluch, José M., Busqué, F., Hernando, Jordi, Gorostiza, Pau, Alibés, Ramon, (2019). Rationally designed azobenzene photoswitches for efficient two-photon neuronal excitation Nature Communications 10, (1), 907

Manipulation of neuronal activity using two-photon excitation of azobenzene photoswitches with near-infrared light has been recently demonstrated, but their practical use in neuronal tissue to photostimulate individual neurons with three-dimensional precision has been hampered by firstly, the low efficacy and reliability of NIR-induced azobenzene photoisomerization compared to one-photon excitation, and secondly, the short cis state lifetime of the two-photon responsive azo switches. Here we report the rational design based on theoretical calculations and the synthesis of azobenzene photoswitches endowed with both high two-photon absorption cross section and slow thermal back-isomerization. These compounds provide optimized and sustained two-photon neuronal stimulation both in light-scattering brain tissue and in Caenorhabditis elegans nematodes, displaying photoresponse intensities that are comparable to those achieved under one-photon excitation. This finding opens the way to use both genetically targeted and pharmacologically selective azobenzene photoswitches to dissect intact neuronal circuits in three dimensions.


Cutrale, Francesco, Rodriguez, Daniel, Hortigüela, Verónica, Chiu, Chi-Li, Otterstrom, Jason, Mieruszynski, Stephen, Seriola, Anna, Larrañaga, Enara, Raya, Angel, Lakadamyali, Melike, Fraser, Scott E., Martinez, Elena, Ojosnegros, Samuel, (2019). Using enhanced number and brightness to measure protein oligomerization dynamics in live cells Nature Protocols 14, 616-638

Protein dimerization and oligomerization are essential to most cellular functions, yet measurement of the size of these oligomers in live cells, especially when their size changes over time and space, remains a challenge. A commonly used approach for studying protein aggregates in cells is number and brightness (N&B), a fluorescence microscopy method that is capable of measuring the apparent average number of molecules and their oligomerization (brightness) in each pixel from a series of fluorescence microscopy images. We have recently expanded this approach in order to allow resampling of the raw data to resolve the statistical weighting of coexisting species within each pixel. This feature makes enhanced N&B (eN&B) optimal for capturing the temporal aspects of protein oligomerization when a distribution of oligomers shifts toward a larger central size over time. In this protocol, we demonstrate the application of eN&B by quantifying receptor clustering dynamics using electron-multiplying charge-coupled device (EMCCD)-based total internal reflection microscopy (TIRF) imaging. TIRF provides a superior signal-to-noise ratio, but we also provide guidelines for implementing eN&B in confocal microscopes. For each time point, eN&B requires the acquisition of 200 frames, and it takes a few seconds up to 2 min to complete a single time point. We provide an eN&B (and standard N&B) MATLAB software package amenable to any standard confocal or TIRF microscope. The software requires a high-RAM computer (64 Gb) to run and includes a photobleaching detrending algorithm, which allows extension of the live imaging for more than an hour.


Kyndiah, A., Leonardi, F., Tarantino, C., Cramer, T., Millan-Solsona, R., Garreta, E., Montserrat, N., Mas-Torrent, M., Gomila, G., (2019). Bioelectronic recordings of cardiomyocytes with accumulation mode electrolyte gated organic field effect transistors Biosensors and Bioelectronics Available online

Organic electronic materials offer an untapped potential for novel tools for low-invasive electrophysiological recording and stimulation devices. Such materials combine semiconducting properties with tailored surface chemistry, elastic mechanical properties and chemical stability in water. In this work, we investigate solution processed Electrolyte Gated Organic Field Effect Transistors (EGOFETs) based on a small molecule semiconductor. We demonstrate that EGOFETs based on a blend of soluble organic semiconductor 2,8-Difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES-ADT) combined with an insulating polymer show excellent sensitivity and long-term recording under electrophysiological applications. Our devices can stably record the extracellular potential of human pluripotent stem cell derived cardiomyocyte cells (hPSCs-CMs) for several weeks. In addition, cytotoxicity tests of pharmaceutical drugs, such as Norepinephrine and Verapamil was achieved with excellent sensitivity. This work demonstrates that organic transistors based on organic blends are excellent bioelectronics transducer for extracellular electrical recording of excitable cells and tissues thus providing a valid alternative to electrochemical transistors.

Keywords: Bioelectronics, Cardiac cells, Organic electronics, Organic field effect transistors, Organic semiconducting blend


Castaño, Albert G., García-Díaz, María, Torras, Núria, Altay, Gizem, Comelles, Jordi, Martínez, Elena, (2019). Dynamic photopolymerization produces complex microstructures on hydrogels in a moldless approach to generate a 3D intestinal tissue model Biofabrication 11, (2), 025007

Epithelial tissues contain three-dimensional (3D) complex microtopographies that are essential for proper performance. These microstructures provide cells with the physicochemical cues needed to guide their self-organization into functional tissue structures. However, most in vitro models do not implement these 3D architectural features. The main problem is the availability of simple fabrication techniques that can reproduce the complex geometries found in native tissues on the soft polymeric materials required as cell culture substrates. In this study reaction-diffusion mediated photolithography is used to fabricate 3D microstructures with complex geometries on poly(ethylene glycol)-based hydrogels in a single step and moldless approach. By controlling fabrication parameters such as the oxygen diffusion/depletion timescales, the distance to the light source and the exposure dose, the dimensions and geometry of the microstructures can be well-defined. In addition, copolymerization of poly(ethylene glycol) with acrylic acid improves control of the dynamic reaction-diffusion processes that govern the free-radical polymerization of highly-diluted polymeric solutions. Moreover, acrylic acid allows adjusting the density of cell adhesive ligands while preserving the mechanical properties of the hydrogels. The method proposed is a simple, single-step, and cost-effective strategy for producing models of intestinal epithelium that can be easily integrated into standard cell culture platforms.


Checa, Marti, Millán, Rubén, Blanco, Núria, Torrents, Eduard, Fabregas, Rene, Gomila, Gabriel, (2019). Mapping the dielectric constant of a single bacterial cell at the nanoscale with scanning dielectric force volume microscopy Nanoscale 11, 20809-20819

Mapping the dielectric constant at the nanoscale of samples showing a complex topography, such as non-planar nanocomposite materials or single cells, poses formidable challenges to existing nanoscale dielectric microscopy techniques. Here we overcome these limitations by introducing Scanning Dielectric Force Volume Microscopy. This scanning probe microscopy technique is based on the acquisition of electrostatic force approach curves at every point of a sample and its post-processing and quantification by using a computational model that incorporates the actual measured sample topography. The technique provides quantitative nanoscale images of the local dielectric constant of the sample with unparalleled accuracy, spatial resolution and statistical significance, irrespectively of the complexity of its topography. We illustrate the potential of the technique by presenting a nanoscale dielectric constant map of a single bacterial cell, including its small-scale appendages. The bacterial cell shows three characteristic equivalent dielectric constant values, namely, εr,bac1=2.6±0.2, εr,bac2=3.6±0.4 and εr,bac3=4.9±0.5, which enable identifying different dielectric properties of the cell wall and of the cytoplasmatic region, as well as, the existence of variations in the dielectric constant along the bacterial cell wall itself. Scanning Dielectric Force Volume Microscopy is expected to have an important impact in Materials and Life Sciences where the mapping of the dielectric properties of samples showing complex nanoscale topographies is often needed.


Ortega, María A., Fernández-Garibay, Xiomara, Castaño, Albert G., De Chiara, Francesco, Hernández-Albors, Alejandro, Balaguer-Trias, Jordina, Ramón-Azcón, Javier, (2019). Muscle-on-a-chip with an on-site multiplexed biosensing system for in situ monitoring of secreted IL-6 and TNF-α Lab on a Chip 19, 2568-2580

Despite the increasing number of organs-on-a-chip that have been developed in the past decade, limited efforts have been made to integrate a sensing system for in situ continual measurements of biomarkers from three-dimensional (3D) tissues. Here, we present a custom-made integrated platform for muscle cell stimulation under fluidic conditions connected with a multiplexed high-sensitivity electrochemical sensing system for in situ monitoring. To demonstrate this, we use our system to measure the release levels and release time of interleukin 6 and tumor necrosis factor alpha in vitro by 3D muscle microtissue under electrical and biological stimulations. Our experimental design has enabled us to perform multiple time point measurements using functionalized screen-printed gold electrodes with sensitivity in the ng mL−1 range. This affordable setup is uniquely suited for monitoring factors released by 3D single cell types upon external stimulation for metabolic studies.


Ohui, K., Afanasenko, E., Bacher, F., Ting, R. L. X., Zafar, A., Blanco-Cabra, N., Torrents, E., Dömötör, O., May, N. V., Darvasiova, D., Enyedy, Éva A., Popovi, Reynisson, J., Rapta, P., Babak, M. V., Pastorin, G., Arion, V. B., (2019). New water-soluble copper(II) complexes with morpholine-thiosemicarbazone hybrids: Insights into the anticancer and antibacterial mode of action Journal of Medicinal Chemistry 62, (2), 512-530

Six morpholine-(iso)thiosemicarbazone hybrids HL1–HL6 and their Cu(II) complexes with good-to-moderate solubility and stability in water were synthesized and characterized. Cu(II) complexes [Cu(L1–6)Cl] (1–6) formed weak dimeric associates in the solid state, which did not remain intact in solution as evidenced by ESI-MS. The lead proligands and Cu(II) complexes displayed higher antiproliferative activity in cancer cells than triapine. In addition, complexes 2–5 were found to specifically inhibit the growth of Gram-positive bacteria Staphylococcus aureus with MIC50 values at 2–5 μg/mL. Insights into the processes controlling intracellular accumulation and mechanism of action were investigated for 2 and 5, including the role of ribonucleotide reductase (RNR) inhibition, endoplasmic reticulum stress induction, and regulation of other cancer signaling pathways. Their ability to moderately inhibit R2 RNR protein in the presence of dithiothreitol is likely related to Fe chelating properties of the proligands liberated upon reduction.


Sadowska, J. M., Guillem-Marti, J., Ginebra, M. P., (2019). The influence of physicochemical properties of biomimetic hydroxyapatite on the in vitro behavior of endothelial progenitor cells and their interaction with mesenchymal stem cells Advanced Healthcare Materials 8, (2), 1801138

Calcium phosphate (CaP) substrates are successfully used as bone grafts due to their osteogenic properties. However, the influence of the physicochemical features of CaPs in angiogenesis is frequently neglected despite it being a crucial process for bone regeneration. The present work focuses on analyzing the effects of textural parameters of biomimetic calcium deficient hydroxyapatite (CDHA) and sintered beta-tricalcium phosphate (β-TCP), such as specific surface area, surface roughness, and microstructure, on the behavior of rat endothelial progenitor cells (rEPCs) and their crosstalk with rat mesenchymal stem cells (rMSCs). The higher reactivity of CDHA results in low proliferation rates in monocultured and cocultured systems. This effect is especially pronounced for rMSCs alone, and for CDHA with a fine microstructure. In terms of angiogenic and osteogenic gene expressions, the upregulation of particular genes is especially enhanced for needle-like CDHA compared to plate-like CDHA and β-TCP, suggesting the importance not only of the chemistry of the substrate, but also of its textural features. Moreover, the coculture of rEPCs and rMSCs on needle-like CDHA results in early upregulation of osteogenic modulator, i.e., protein deglycase 1 might be a possible cause of overexpression of osteogenic-related genes on the same substrate.

Keywords: Angiogenesis, Calcium phosphates, Cocultures, Osteogenesis


Mestres, G., Fernandez-Yague, M. A., Pastorino, D., Montufar, E. B., Canal, C., Manzanares-Céspedes, M. C., Ginebra, M. P., (2019). In vivo efficiency of antimicrobial inorganic bone grafts in osteomyelitis treatments Materials Science and Engineering: C 97, 84-95

The purpose of the present work was to evaluate in vivo different antimicrobial therapies to eradicate osteomyelitis created in the femoral head of New Zealand rabbits. Five phosphate-based cements were evaluated: calcium phosphate cements (CPC) and calcium phosphate foams (CPF), both in their pristine form and loaded with doxycycline hyclate, and an intrinsic antimicrobial magnesium phosphate cement (MPC; not loaded with an antibiotic). The cements were implanted in a bone previously infected with Staphylococcus aureus to discern the effects of the type of antibiotic administration (systemic vs. local), porosity (microporosity, i.e. <5 μm vs. macroporosity, i.e. >5 μm) and type of antimicrobial mechanism (release of antibiotic vs. intrinsic antimicrobial activity) on the improvement of the health state of the infected animals. A new method was developed, with a more comprehensive composite score that integrates 5 parameters of bone infection, 4 parameters of bone structural integrity and 4 parameters of bone regeneration. This method was used to evaluate the health state of the infected animals, both before and after osteomyelitis treatment. The results showed that the composite score allows to discern statistically significant differences between treatments that individual evaluations were not able to identify. Despite none of the therapies completely eradicated the infection, it was observed that macroporous materials (CPF and CPFd, the latter loaded with doxycycline hyclate) and intrinsic antimicrobial MPC allowed a better containment of the osteomyelitis. This study provides novel insights to understand the effect of different antimicrobial therapies in vivo, and a promising comprehensive methodology to evaluate the health state of the animals was developed. We expect that the implementation of such methodology could improve the criteria to select a proper antimicrobial therapy.

Keywords: Calcium phosphate cements, Calcium phosphate foams, Drug delivery, In vivo, Magnesium phosphate cements, Osteomyelitis


Martinez, Elena, St-Pierre, Jean-Philippe, Variola, Fabio, (2019). Advanced bioengineering technologies for preclinical research Advances in Physics: X 4, (1), 1622451

ABSTRACTCurrent in vitro practices must overcome important challenges to compare favorably with human studies. The limited applicability of conventional in vitro assays and strategies can be explained by the fact that standard approaches do not enable recapitulation of the complexity of human tissues and physiological functions. To address this challenge, novel bioengineering tools, techniques and technologies are rapidly emerging to advance current fundamental knowledge and innovate in vitro practices. For example, organs-on-a-chip have recently appeared as a small-scale solution to overcome the transability, financial and ethical concerns associated with animal studies in drug discovery and development. In parallel, biomimetic interfaces are increasingly recapitulating 3D structures with tissue-like dynamic properties to allow in-depth investigation of disease mechanisms. This review aims at highlighting current bioengineering approaches poised to address the shortcomings of conventional in vitro research practices towards the generation of more effective solutions for improving human health.


Mestre, Rafael, Patiño, Tania, Barceló, Xavier, Anand, Shivesh, Pérez-Jiménez, Ariadna, Sánchez, Samuel, (2019). Force modulation and adaptability of 3D-bioprinted biological actuators based on skeletal muscle tissue Advanced Materials Technologies 4, (2), 1800631

Abstract The integration of biological systems into robotic devices might provide them with capabilities acquired from natural systems and significantly boost their performance. These abilities include real-time bio-sensing, self-organization, adaptability, or self-healing. As many muscle-based bio-hybrid robots and bio-actuators arise in the literature, the question of whether these features can live up to their expectations becomes increasingly substantial. Herein, the force generation and adaptability of skeletal-muscle-based bio-actuators undergoing long-term training protocols are analyzed. The 3D-bioprinting technique is used to fabricate bio-actuators that are functional, responsive, and have highly aligned myotubes. The bio-actuators are 3D-bioprinted together with two artificial posts, allowing to use it as a force measuring platform. In addition, the force output evolution and dynamic gene expression of the bio-actuators are studied to evaluate their degree of adaptability according to training protocols of different frequencies and mechanical stiffness, finding that their force generation could be modulated to different requirements. These results shed some light into the fundamental mechanisms behind the adaptability of muscle-based bio-actuators and highlight the potential of using 3D bioprinting as a rapid and cost-effective tool for the fabrication of custom-designed soft bio-robots.


Hortigüela, Verónica, Larrañaga, Enara, Lagunas, Anna, Acosta, Gerardo A., Albericio, Fernando, Andilla, Jordi, Loza-Alvarez, Pablo, Martínez, Elena, (2019). Large-area biomolecule nanopatterns on diblock copolymer surfaces for cell adhesion studies Nanomaterials 9, (4), 579

Cell membrane receptors bind to extracellular ligands, triggering intracellular signal transduction pathways that result in specific cell function. Some receptors require to be associated forming clusters for effective signaling. Increasing evidences suggest that receptor clustering is subjected to spatially controlled ligand distribution at the nanoscale. Herein we present a method to produce in an easy, straightforward process, nanopatterns of biomolecular ligands to study ligand–receptor processes involving multivalent interactions. We based our platform in self-assembled diblock copolymers composed of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) that form PMMA nanodomains in a closed-packed hexagonal arrangement. Upon PMMA selective functionalization, biomolecular nanopatterns over large areas are produced. Nanopattern size and spacing can be controlled by the composition of the block-copolymer selected. Nanopatterns of cell adhesive peptides of different size and spacing were produced, and their impact in integrin receptor clustering and the formation of cell focal adhesions was studied. Cells on ligand nanopatterns showed an increased number of focal contacts, which were, in turn, more matured than those found in cells cultured on randomly presenting ligands. These findings suggest that our methodology is a suitable, versatile tool to study and control receptor clustering signaling and downstream cell behavior through a surface-based ligand patterning technique.


Altay, Gizem, Larrañaga, Enara, Tosi, Sébastien, Barriga, Francisco M., Batlle, Eduard, Fernández-Majada, Vanesa, Martínez, Elena, (2019). Self-organized intestinal epithelial monolayers in crypt and villus-like domains show effective barrier function Scientific Reports 9, (1), 10140

Intestinal organoids have emerged as a powerful in vitro tool for studying intestinal biology due to their resemblance to in vivo tissue at the structural and functional levels. However, their sphere-like geometry prevents access to the apical side of the epithelium, making them unsuitable for standard functional assays designed for flat cell monolayers. Here, we describe a simple method for the formation of epithelial monolayers that recapitulates the in vivo-like cell type composition and organization and that is suitable for functional tissue barrier assays. In our approach, epithelial monolayer spreading is driven by the substrate stiffness, while tissue barrier function is achieved by the basolateral delivery of medium enriched with stem cell niche and myofibroblast-derived factors. These monolayers contain major intestinal epithelial cell types organized into proliferating crypt-like domains and differentiated villus-like regions, closely resembling the in vivo cell distribution. As a unique characteristic, these epithelial monolayers form functional epithelial barriers with an accessible apical surface and physiologically relevant transepithelial electrical resistance values. Our technology offers an up-to-date and novel culture method for intestinal epithelium, providing an in vivo-like cell composition and distribution in a tissue culture format compatible with high-throughput drug absorption or microbe-epithelium interaction studies.


Lozano, H., Millán-Solsona, R., Fabregas, R., Gomila, G., (2019). Sizing single nanoscale objects from polarization forces Scientific Reports 9, (1), 14142

Sizing natural or engineered single nanoscale objects is fundamental in many areas of science and technology. To achieve it several advanced microscopic techniques have been developed, mostly based on electron and scanning probe microscopies. Still for soft and poorly adhered samples the existing techniques face important challenges. Here, we propose an alternative method to size single nanoscale objects based on the measurement of its electric polarization. The method is based on Electrostatic Force Microscopy measurements combined with a specifically designed multiparameter quantification algorithm, which gives the physical dimensions (height and width) of the nanoscale object. The proposed method is validated with ~50 nm diameter silver nanowires, and successfully applied to ~10 nm diameter bacterial polar flagella, an example of soft and poorly adhered nanoscale object. We show that an accuracy comparable to AFM topographic imaging can be achieved. The main advantage of the proposed method is that, being based on the measurement of long-range polarization forces, it can be applied without contacting the sample, what is key when considering poorly adhered and soft nanoscale objects. Potential applications of the proposed method to a wide range of nanoscale objects relevant in Material, Life Sciences and Nanomedicine is envisaged.

Keywords: Characterization and analytical techniques, Imaging techniques


Manconi, M., Manca, M. L., Escribano-Ferrer, E., Coma-Cros, E. M., Biosca, A., Lantero, E., Fernàndez-Busquets, X., Fadda, A. M., Caddeo, C., (2019). Nanoformulation of curcumin-loaded eudragit-nutriosomes to counteract malaria infection by a dual strategy: Improving antioxidant intestinal activity and systemic efficacy International Journal of Pharmaceutics 556, 82-88

In this paper, nutriosomes (phospholipid vesicles associated with Nutriose® FM06) were modified to obtain new systems aimed at enhancing the efficacy of curcumin in counteracting malaria infection upon oral administration. Eudragit® L100, a pH-sensitive co-polymer, was added to these vesicles, thus obtaining eudragit-nutriosomes, to improve their in vivo performances. Liposomes without eudragit and nutriose were also prepared as a reference. Cryo-TEM images showed the formation of multicompartment vesicles, with mean diameter around 300 nm and highly negative zeta potential. Vesicles were stable in fluids mimicking the gastro-intestinal content due to the high phospholipid concentration and the presence of gastro-resistant eudragit and digestion-resistant nutriose. Eudragit-nutriosomes disclosed promising performances in vitro and in vivo: they maximized the ability of curcumin to counteract oxidative stress in intestinal cells (Caco-2), which presumably reinforced its systemic efficacy. Orally-administered curcumin-loaded eudragit-nutriosomes increased significantly the survival of malaria-infected mice relative to free curcumin-treated controls.

Keywords: Eudragit® L100, Nutriose® FM06, Nutriosomes, Curcumin, Oral administration, Malaria


de Goede, M., Dijkstra, M., Obregón, R., Ramón-Azcón, J., Martínez, E., Padilla, L., Mitjans, F., Garcia-Blanco, S. M., (2019). Al2O3 microring resonators for the detection of a cancer biomarker in undiluted urine Optics Express 27, (13), 18508-18521

Concentrations down to 3 nM of the rhS100A4 protein, associated with human tumor development, have been detected in undiluted urine using an integrated sensor based on microring resonators in the emerging Al2O3 photonic platform. The fabricated microrings were designed for operation in the C-band (λ = 1565 nm) and exhibited a high-quality factor in air of 3.2 × 105. The bulk refractive index sensitivity of the devices was ~100 nm/RIU (for TM polarization) with a limit of detection of ~10−6 RIU. A surface functionalization protocol was developed to allow for the selective binding of the monoclonal antibodies designed to capture the target biomarker to the surface of the Al2O3 microrings. The detection of rhS100A4 proteins at clinically relevant concentrations in urine is a big milestone towards the use of biosensors for the screening and early diagnosis of different cancers. Biosensors based on this microring technology can lead to portable, multiplexed and easy-to-use point of care devices.

Keywords: Distributed feedback lasers, Effective refractive index, Laser coupling, Polarization maintaining fibers, Refractive index, Scanning electron microscopy


Rafols-de-Urquia, M., Estrada, L., Estevez-Piorno, J., Sarlabous, L., Jane, R., Torres, A., (2019). Evaluation of a wearable device to determine cardiorespiratory parameters from surface diaphragm electromyography IEEE Journal of Biomedical and Health Informatics Early Access

The use of wearable devices in clinical routines could reduce healthcare costs and improve the quality of assessment in patients with chronic respiratory diseases. The purpose of this study is to evaluate the capacity of a Shimmer3 wearable device to extract reliable cardiorespiratory parameters from surface diaphragm electromyography (EMGdi). Twenty healthy volunteers underwent an incremental load respiratory test whilst EMGdi was recorded with a Shimmer3 wearable device (EMGdiW). Simultaneously, a second EMGdi (EMGdiL), inspiratory mouth pressure (Pmouth) and lead-I electrocardiogram (ECG) were recorded via a standard wired laboratory acquisition system. Different cardiorespiratory parameters were extracted from both EMGdiW and EMGdiL signals: heart rate, respiratory rate, respiratory muscle activity and mean frequency of EMGdi signals. Alongside these, similar parameters were also extracted from reference signals (Pmouth and ECG). High correlations were found between the data extracted from the EMGdiW and the reference signal data: heart rate (R = 0.947), respiratory rate (R = 0.940), respiratory muscle activity (R = 0.877), and mean frequency (R = 0.895). Moreover, similar increments in EMGdiW and EMGdiL activity were observed when Pmouth was raised, enabling the study of respiratory muscle activation. In summary, the Shimmer3 device is a promising and cost-effective solution for the ambulatory monitoring of respiratory muscle function in chronic respiratory diseases. IEEE

Keywords: Cardiorespiratory monitoring, Chronic respiratory diseases, Fixed sample entropy, Non-invasive respiratory monitoring, Surface diaphragm electromyography, Wearable wireless device


Nevola, Laura, Varese, Monica, Martín-Quirós, Andrés, Mari, Giacomo, Eckelt, Kay, Gorostiza, Pau, Giralt, Ernest, (2019). Targeted nanoswitchable inhibitors of protein-protein interactions involved in apoptosis ChemMedChem 14, 100-106

Progress in drug delivery is hampered by the lack of efficient strategies to target drugs with high specificity and precise spatiotemporal regulation. The remote control of nanoparticles and drugs with light allows controlling their action site and dosage. Peptide-based drugs are very specific, non-immunogenic and can be designed to cross the plasma membrane. In order to combine target specificity and remote control of drug action, here we describe a versatile strategy based on a generalized template to design nanoswitchable peptides that modulate protein-protein interactions with light. This approach is demonstrated to photomodulate two important targets involved in apoptosis (the interactions Bcl-xL/Bak and MDM2/p53), but can be applied to a large pool of therapeutically relevant protein-protein interactions mediated by alpha helical motifs. The template can be adjusted using readily available information about the hot spots (residues contributing most to the binding energy) at the protein-protein interface of interest.


Checa, M., Millan-Solsona, R., Gomila, G., (2019). Frequency-dependent force between ac-voltage-biased plates in electrolyte solutions Physical Review E 100, (2), 022604

We analyze the frequency dependence of the force between ac-voltage-biased plates in electrolyte solutions. To this end we solve analytically the Poisson-Nernst-Planck transport model in the dilute concentration and low voltage regime for a 1:1 symmetric electrolyte with blocking electrodes under a dc+ac applied voltage. The total force, which is the resultant of the electric and osmotic forces, shows a complex dependence on plate separation, frequency, ion concentration, and compact layer properties, different from that predicted from electrostatic current models or equivalent circuit models, due to the relevance of the osmotic force contribution in almost the whole range of frequencies. For the total dc force, we show that it decays at fixed ion concentration, linearly with plate separation for separations larger than a few times the Debye screening length. This linear dependence is due to the assumption about the conservation of the number of ions in the system. Moreover, the 1ω and 2ω ac harmonics of the total force show a broad peak at intermediate frequencies; it is centered at about the inverse of the charging time of the double layer capacitance, and covers the frequency range between the inverse of the diffusion time and the inverse of the electrolyte dielectric relaxation time. Finally, the 1ω ac harmonic component attains its high frequency asymptotic value at frequencies much higher than the inverse of the electrolyte dielectric relaxation time due to the very slow relaxation of the osmotic 1ω harmonic component at high frequencies. The derived analytical expressions for the total force remain valid up to voltages of the order of the thermal voltage, as has been assessed by means of numerical calculations. The numerical calculations are also used to explore the onset of higher force harmonics for larger applied voltages. Understanding the frequency dependence of the force acting on voltage-biased plates in electrolyte solutions can be of relevance for electrical actuation strategies in microelectromechanical systems and for the interpretation of some emerging electric scanning probe force microscopy techniques operating in electrolyte solutions.

Keywords: Electrochemistry, Statistical physics


Vidal, E., Buxadera-Palomero, J., Pierre, C., Manero, J. M., Ginebra, M. P., Cazalbou, S., Combes, C., Rupérez, E., Rodríguez, D., (2019). Single-step pulsed electrodeposition of calcium phosphate coatings on titanium for drug delivery Surface and Coatings Technology 358, 266-275

Metallic implants have some limitations related to bioactivity and bacteria colonization leading to infections. In this regard, calcium phosphate coatings can be used as carrier for drug delivery in order to improve the mentioned drawbacks. The present work proposes the introduction of an antibacterial agent in the course of a pulsed and reverse pulsed electrodeposition. Calcium phosphate coatings were prepared in 30 min using different pulse waveforms (unipolar-bipolar), current densities (2–5 mA/cm2) and temperatures (40–60 °C). Mechanical stability of the as-coated surfaces was studied in order to select the optimal electrodeposition conditions. Subsequently, selected coatings were loaded with an antiseptic agent, chlorhexidine digluconate (CHX), via a single-step co-deposition procedure. CHX concentration added to the electrolyte was adjusted to 3 mM based on the antibacterial efficacy of the loaded coatings evaluated in vitro with Staphylococcus aureus and Escherichia coli bacteria strains. Whereas the same chlorhexidine concentration was added to the electrolyte, results showed that the amount of CHX loaded was different for each condition while release kinetics was maintained. The results of this work demonstrate that a pulsed co-deposition strategy has great potential to modulate local delivery of antibacterial agents such as chlorhexidine digluconate, which may prevent early phase infections of metallic implants after insertion.

Keywords: Antibacterial agent, Calcium phosphate, Characterization, Coating, Pulse electrodeposition, Titanium


Oliveira, V. R., Uriarte, J. J., Falcones, B., Zin, W. A., Navajas, D., Farré, R., Almendros, I., (2019). Escherichia coli lipopolysaccharide induces alveolar epithelial cell stiffening Journal of Biomechanics 83, 315-318

Introduction: Application of lipopolysaccharide (LPS) is a widely employed model to mimic acute respiratory distress syndrome (ARDS). Available data regarding LPS-induced biomechanical changes on pulmonary epithelial cells are limited only to P. aeruginosa LPS. Considering that LPS from different bacteria could promote a specific mechanical response in epithelial cells, we aim to assess the effect of E. coli LPS, widely employed as a model of ARDS, in the biomechanics of alveolar epithelial cells. Methods: Young’s modulus (E) of alveolar epithelial cells (A549) was measured by atomic force microscopy every 5 min throughout 60 min of experiment after treatment with LPS from E. coli (100 μg/mL). The percentage of cells presenting actin stress fibers (F-actin staining) was also evaluated. Control cells were treated with culture medium and the values obtained were compared with LPS-treated cells for each time-point. Results: Application of LPS induced significant increase in E after 20 min (77%) till 60 min (104%) in comparison to controls. Increase in lung epithelial cell stiffness induced by LPS was associated with a higher number of cells presenting cytoskeletal remodeling. Conclusions: The observed effects of E. coli LPS on alveolar epithelial cells suggest that this widely-used LPS is able to promote a quick formation of actin stress fibers and stiffening cells, thereby facilitating the disruption of the pulmonary epithelial barrier.

Keywords: Acute respiratory distress syndrome model, Alveolar epithelium, Biomechanics, E. coli, Lipopolysaccharide


Ruzzene, G., Omelchenko, I., Schöl, E., Zakharova, A., Andrzejak, R. G. , (2019). Controlling chimera states via minimal coupling modification Chaos: An Interdisciplinary Journal of Nonlinear Science 29, (5), 051103

We propose a method to control chimera states in a ring-shaped network of nonlocally coupled phase oscillators. This method acts exclusively on the network’s connectivity. Using the idea of a pacemaker oscillator, we investigate which is the minimal action needed to control chimeras. We implement the pacemaker choosing one oscillator and making its links unidirectional. Our results show that a pacemaker induces chimeras for parameters and initial conditions for which they do not form spontaneously. Furthermore, the pacemaker attracts the incoherent part of the chimera state, thus controlling its position. Beyond that, we find that these control effects can be achieved with modifications of the network’s connectivity that are less invasive than a pacemaker, namely, the minimal action of just modifying the strength of one connection allows one to control chimeras.

Keywords: Complex networks, Oscillators, Spatiotemporal phenomena


Pellequer, J. L., Parot, P., Navajas, D., Kumar, S., Svetli, Scheuring, S., Hu, J., Li, B., Engler, A., Sousa, S., Lekka, M., Szymo, Schillers, H., Odorico, M., Lafont, F., Janel, S., Rico, F., (2019). Fifteen years of Servitude et Grandeur to the application of a biophysical technique in medicine: The tale of AFMBioMed Journal of Molecular Recognition 32, (3), e2773

AFMBioMed is the founding name under which international conferences and summer schools are organized around the application of atomic force microscopy in life sciences and nanomedicine. From its inception at the Atomic Energy Commission in Marcoule near 2004 to its creation in 2007 and to its 10th anniversary conference in Krakow, a brief narrative history of its birth and rise will demonstrate how and what such an organization brings to laboratories and the AFM community. With the current planning of the next AFMBioMed conference in Münster in 2019, it will be 15 years of commitment to these events.

Keywords: Atomic Force Microscopy, Single molecules, Biomechanics, Force spectroscopy, High-speed AFM, Imaging, Nanoindentation, Nanomedicine, Nanotoxicology


Trebicka, J., Amoros, A., Pitarch, C., Titos, E., Alcaraz-Quiles, J., Schierwagen, R., Deulofeu, C., Fernandez-Gomez, J., Piano, S., Caraceni, P., Oettl, K., Sola, E., Laleman, W., McNaughtan, J., Mookerjee, R. P., Coenraad, M. J., Welzel, T., Steib, C., Garcia, R., Gustot, T., Rodriguez Gandia, M. A., Bañares, R., Albillos, A., Zeuzem, S., Vargas, V., Saliba, F., Nevens, F., Alessandria, C., De Gottardi, A., Zoller, H., Ginès, P., Sauerbruch, T., Gerbes, A., Stauber, R. E., Bernardi, M., Angeli, P., Pavesi, M., Moreau, R., Clària, J., Jalan, R., Arroyo, V., (2019). Addressing profiles of systemic inflammation across the different clinical phenotypes of acutely decompensated cirrhosis Frontiers in Immunology 10, 476

Background: Patients with acutely decompensated cirrhosis (AD) may or may not develop acute-on-chronic liver failure (ACLF). ACLF is characterized by high-grade systemic inflammation, organ failures (OF) and high short-term mortality. Although patients with AD cirrhosis exhibit distinct clinical phenotypes at baseline, they have low short-term mortality, unless ACLF develops during follow-up. Because little is known about the association of profile of systemic inflammation with clinical phenotypes of patients with AD cirrhosis, we aimed to investigate a battery of markers of systemic inflammation in these patients. Methods: Upon hospital admission baseline plasma levels of 15 markers (cytokines, chemokines, and oxidized albumin) were measured in 40 healthy controls, 39 compensated cirrhosis, 342 AD cirrhosis, and 161 ACLF. According to EASL-CLIF criteria, AD cirrhosis was divided into three distinct clinical phenotypes (AD-1: Creatinine<1.5, no HE, no OF; AD-2: creatinine 1.5–2, and or HE grade I/II, no OF; AD-3: Creatinine<1.5, no HE, non-renal OF). Results: Most markers were slightly abnormal in compensated cirrhosis, but markedly increased in AD. Patients with ACLF exhibited the largest number of abnormal markers, indicating “full-blown” systemic inflammation (all markers). AD-patients exhibited distinct systemic inflammation profiles across three different clinical phenotypes. In each phenotype, activation of systemic inflammation was only partial (30% of the markers). Mortality related to each clinical AD-phenotype was significantly lower than mortality associated with ACLF (p < 0.0001 by gray test). Among AD-patients baseline systemic inflammation (especially IL-8, IL-6, IL-1ra, HNA2 independently associated) was more intense in those who had poor 28-day outcomes (ACLF, death) than those who did not experience these outcomes. Conclusions: Although AD-patients exhibit distinct profiles of systemic inflammation depending on their clinical phenotypes, all these patients have only partial activation of systemic inflammation. However, those with the most extended baseline systemic inflammation had the highest the risk of ACLF development and death.

Keywords: ACLF, Acute decompensation, Cirrhosis, Organ dysfunction, Organ failure, Signature


de Goede, Michiel, Chang, Lantian, Mu, Jinfeng, Dijkstra, Meindert, Obregón, Raquel, Martínez, Elena, Padilla, Laura, Mitjans, Francesc, Garcia-Blanco, Sonia M., (2019). Al2O3:Yb3+ integrated microdisk laser label-free biosensor Optics Letters 44, (24), 5937-5940

Whispering gallery mode resonator lasers hold the promise of an ultralow intrinsic limit of detection. However, the widespread use of these devices for biosensing applications has been hindered by the complexity and lack of robustness of the proposed configurations. In this work, we demonstrate biosensing with an integrated microdisk laser. Al2O3doped with Yb3+ was utilized because of its low optical losses as well as its emission in the range 1020–1050 nm, outside the absorption band of water. Single-mode laser emission was obtained at a wavelength of 1024 nm with a linewidth of 250 kHz while the microdisk cavity was submerged in water. A limit of detection of 300 pM (3.6 ng/ml) of the protein rhS100A4 in urine was experimentally demonstrated, showing the potential of the proposed devices for biosensing.

Keywords: Distributed feedback lasers, Fiber lasers, Laser modes, Microdisk lasers, Single mode lasers, Tunable lasers


Caddeo, C., Gabriele, M., Fernàndez-Busquets, X., Valenti, D., Fadda, A. M., Pucci, L., Manconi, M., (2019). Antioxidant activity of quercetin in Eudragit-coated liposomes for intestinal delivery International Journal of Pharmaceutics 565, 64-69

Quercetin, a natural polyphenol with strong antioxidant activity, was loaded in Eudragit-coated liposomes conceived for intestinal delivery. Eudragit was used to form a protective shell on the surface of liposomes to resist gastric environment and allow the delivery of quercetin to the intestine. The physico-chemical properties of the liposomes were assessed by light scattering and cryogenic transmission electron microscopy. Small, spherical, uni- and bilamellar liposomes were produced, with the presence of multilamellar structures in Eudragit-coated liposomes. The Eudragit coating increased the physical stability of the vesicular system in fluids mimicking the gastrointestinal environment. Further, the incorporation of quercetin in the vesicular system did not affect its intrinsic antioxidant activity, as DPPH radical was almost completely inhibited, and the vesicles were also capable of ensuring optimal protection against oxidative stress in human intestinal cells by reducing reactive oxygen species (ROS)production. The proposed approach based on quercetin vesicular formulations may be of value in the treatment of pathological conditions associated with intestinal oxidative stress.

Keywords: Antioxidant, Eudragit, HT-29 cells, Intestinal delivery, Liposomes, Quercetin


Palacín, J., Martínez, D., Clotet, E., Pallejà, T., Burgués, J., Fonollosa, J., Pardo, A., Marco, Santiago, (2019). Application of an array of metal-oxide semiconductor gas sensors in an assistant personal robot for early gas leak detection Sensors 19, (9), 1957

This paper proposes the application of a low-cost gas sensor array in an assistant personal robot (APR) in order to extend the capabilities of the mobile robot as an early gas leak detector for safety purposes. The gas sensor array is composed of 16 low-cost metal-oxide (MOX) gas sensors, which are continuously in operation. The mobile robot was modified to keep the gas sensor array always switched on, even in the case of battery recharge. The gas sensor array provides 16 individual gas measurements and one output that is a cumulative summary of all measurements, used as an overall indicator of a gas concentration change. The results of preliminary experiments were used to train a partial least squares discriminant analysis (PLS-DA) classifier with air, ethanol, and acetone as output classes. Then, the mobile robot gas leak detection capabilities were experimentally evaluated in a public facility, by forcing the evaporation of (1) ethanol, (2) acetone, and (3) ethanol and acetone at different locations. The positive results obtained in different operation conditions over the course of one month confirmed the early detection capabilities of the proposed mobile system. For example, the APR was able to detect a gas leak produced inside a closed room from the external corridor due to small leakages under the door induced by the forced ventilation system of the building.

Keywords: Metal-oxide semiconductor, Gas sensor, Gas leak detection, Assistant personal robot, Mobile robot


Montero, Joan, (2019). The attack of the “seeding” clones Science Translational Medicine 11, (483), eaax0872

Tumor clone tracking in breast cancer xenografts identifies a small subset of circulating tumor cells as “seeders” associated with metastasis.


Grechuta, K., Rubio Ballester, B., Espín Munne, R., Usabiaga Bernal, T., Molina Hervás, B., Mohr, B., Pulvermüller, F., San Segundo, R., Verschure, P., (2019). Augmented dyadic therapy boosts recovery of language function in patients with nonfluent aphasia Stroke 50, (5), 1270-1274

Background and Purpose- Evidence suggests that therapy can be effective in recovering from aphasia, provided that it consists of socially embedded, intensive training of behaviorally relevant tasks. However, the resources of healthcare systems are often too limited to provide such treatment at sufficient dosage. Hence, there is a need for evidence-based, cost-effective rehabilitation methods. Here, we asked whether virtual reality-based treatment grounded in the principles of use-dependent learning, behavioral relevance, and intensity positively impacts recovery from nonfluent aphasia. Methods- Seventeen patients with chronic nonfluent aphasia underwent intensive therapy in a randomized, controlled, parallel-group trial. Participants were assigned to the control group (N=8) receiving standard treatment or to the experimental group (N=9) receiving augmented embodied therapy with the Rehabilitation Gaming System for aphasia. All Rehabilitation Gaming System for aphasia sessions were supervised by an assistant who monitored the patients but did not offer any elements of standard therapy. Both interventions were matched for intensity and materials. Results- Our results revealed that at the end of the treatment both groups significantly improved on the primary outcome measure (Boston Diagnostic Aphasia Examination: control group, P=0.04; experimental group, P=0.01), and the secondary outcome measure (lexical access-vocabulary test: control group, P=0.01; experimental group, P=0.007). However, only the Rehabilitation Gaming System for aphasia group improved on the Communicative Aphasia Log ( P=0.01). The follow-up assessment (week 16) demonstrated that while both groups retained vocabulary-related changes (control group, P=0.01; experimental group, P=0.007), only the Rehabilitation Gaming System for aphasia group showed therapy-induced improvements in language ( P=0.01) and communication ( P=0.05). Conclusions- Our results demonstrate the effectiveness of Rehabilitation Gaming System for aphasia for improving language and communication in patients with chronic aphasia suggesting that current challenges faced by the healthcare system in the treatment of stroke might be effectively addressed by augmenting traditional therapy with computer-based methods. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02928822.

Keywords: Aphasia, Embodied training, Neurological rehabilitation, Virtual reality


Arsiwalla, X. D., Bote, R. M., Verschure, P., (2019). Beyond neural coding? Lessons from perceptual control theory The Behavioral and brain sciences 42, e217

Pointing to similarities between challenges encountered in today's neural coding and twentieth-century behaviorism, we draw attention to lessons learned from resolving the latter. In particular, Perceptual Control Theory posits behavior as a closed-loop control process with immediate and teleological causes. With two examples, we illustrate how these ideas may also address challenges facing current neural coding paradigms.


Oliveira, V. R., Uriarte, J. J., Falcones, B., Jorba, I., Zin, W. A., Farré, R., Navajas, D., Almendros, I., (2019). Biomechanical response of lung epithelial cells to iron oxide and titanium dioxide nanoparticles Frontiers in Physiology 10, 1047

Increasing evidence shows that lungs can be damaged by inhalation of nanoparticles (NPs) at environmental and occupational settings. Recent findings have associated the exposure to iron oxide (Fe2O3) and titanium dioxide (TiO2) – NPs widely used in biomedical and clinical research – with pulmonary oxidative stress and inflammation. Although changes on cellular mechanics could contribute to pulmonary inflammation, there is no information regarding the effects of Fe2O3 and TiO2 on alveolar epithelial cell biomechanics. The aim was to investigate the NPs-induced biomechanical effects in terms of cell stiffness and traction forces exerted by human alveolar epithelial cells. Cell Young’s modulus (E) measured by atomic force microscopy in alveolar epithelial cells significantly decreased after exposure to Fe2O3 and TiO2 (-28 and -25%, respectively) compared to control conditions. Moreover, both NPs induced a similar reduction in the traction forces exerted by the alveolar epithelial cells in comparison to the control conditions. Accordingly, immunofluorescence images revealed a reduction of actomyosin stress fibers in response to the exposure to NPs. However, no inflammatory response was detected. In conclusion, an acute exposure of epithelial pulmonary cells to Fe2O3 and TiO2 NPs, which was mild since it was non-cytotoxic and did not induce inflammation, modified cell biomechanical properties which could be translated into damage of the epithelial barrier integrity, suggesting that mild environmental inhalation of Fe2O3 and TiO2 NPs could not be innocuous.

Keywords: Actomyosin fibers, Air pollution, Cell biomechanics, Lung epithelium, Nanoparticles


Nonaka, P. N., Falcones, B., Farre, R., Artigas, A., Almendros, I., Navajas, D., (2019). Biophysically preconditioning mesenchymal stem cells improves treatment of ventilator-induced lung injury Archivos de Bronconeumología Archivos de Bronconeumologia , In press

Blithikioti, C., Miquel, L., Batalla, A., Rubio, B., Maffei, G., Herreros, I., Gual, A., Verschure, P., Balcells-Oliveró, M., (2019). Cerebellar alterations in cannabis users: A systematic review Addiction Biology Online Version of Record before inclusion in an issue

Cannabis is the most used illicit substance in the world. As many countries are moving towards decriminalization, it is crucial to determine whether and how cannabis use affects human brain and behavior. The role of the cerebellum in cognition, emotion, learning, and addiction is increasingly recognized. Because of its high density in CB1 receptors, it is expected to be highly affected by cannabis use. The aim of this systematic review is to investigate how cannabis use affects cerebellar structure and function, as well as cerebellar‐dependent behavioral tasks. Three databases were searched for peer‐reviewed literature published until March 2018. We included studies that focused on cannabis effects on cerebellar structure, function, or cerebellar‐dependent behavioral tasks. A total of 348 unique records were screened, and 40 studies were included in the qualitative synthesis. The most consistent findings include (1) increases in cerebellar gray matter volume after chronic cannabis use, (2) alteration of cerebellar resting state activity after acute or chronic use, and (3) deficits in memory, decision making, and associative learning. Age of onset and higher exposure to cannabis use were frequently associated with increased cannabis‐induced alterations. Chronic cannabis use is associated with alterations in cerebellar structure and function, as well as with deficits in behavioral paradigms that involve the cerebellum (eg, eyeblink conditioning, memory, and decision making). Future studies should consider tobacco as confounding factor and use standardized methods for assessing cannabis use. Paradigms exploring the functional activity of the cerebellum may prove useful as monitoring tools of cannabis‐induced impairment.

Keywords: Behavior, Cannabis use, Cerebellum, Cognitive function, Structure


Lehmann, J., Praktiknjo, M., Nielsen, M. J., Schierwagen, R., Meyer, C., Thomas, D., Violi, F., Strassburg, C. P., Bendtsen, F., Moller, S., Krag, A., Karsdal, M. A., Leeming, D. J., Trebicka, J., (2019). Collagen type IV remodelling gender-specifically predicts mortality in decompensated cirrhosis Liver International 39, (5), 885-893

Background & Aims: Remodelling of extracellular matrix is crucial in progressive liver fibrosis. Collagen type III desposition has been shown in acute decompensation. Extratracellular matrix is compiled of deposition of various components. The role of basement membrane collagen type IV in advanced cirrhosis and acute decompensation is unclear and investigated in this study. Methods: Patients with decompensated cirrhosis from the prospective NEPTUN cohort (ClinicalTrials.gov Identifier: NCT03628807), who underwent transjugular intrahepatic portosystemic shunt procedure were included. Clinical and laboratory parameters, PRO-C4 and C4M levels were measured in blood samples from portal and hepatic veins just before transjugular intrahepatic portosystemic shunt placement. Results: Levels of C4M and PRO-C4 are significantly lower in patients with massive ascites and impaired renal sodium excretion. C4M and PRO-C4 show gender-specific profiles with significantly lower levels in females compared to males. Females with higher C4M levels show higher mortality. By contrast, males with higher C4M levels show lower mortality. In multivariate Cox regression analysis, C4M is an independent predictor of survival in female patients. Conclusion: This study shows that markers of collagen type IV remodelling do not accumulate in severe renal dysfunction. Although collagen type IV degradation markers derive from the liver, portal venous C4M levels are relevant for survival. Moreover, it demonstrates that circulating C4M shows gender-specific profiles, which can independently predict survival in female patients with decompensated cirrhosis.

Keywords: ACLF, Acute decompensation, Acute-on-chronic liver failure, Cirrhosis, Collagen type IV, Extracellular matrix remodelling, Gender, Liver, Portal hypertension, Transjugular intrahepatic portosystemic shunt


Brol, M. J., Rösch, F., Schierwagen, R., Magdaleno, F., Uschner, F. E., Manekeller, S., Queck, A., Schwarzkopf, K., Odenthal, M., Drebber, U., Thiele, M., Lingohr, P., Plamper, A., Kristiansen, G., Lotersztajn, S., Krag, A., Klein, S., Rheinwalt, K. P., Trebicka, J., Galaxy, Consortium, (2019). Combination of CCL4 with alcoholic and metabolic injuries mimics human liver fibrosis American Journal of Physiology - Gastrointestinal and Liver Physiology 317, (2), G182-G194

Metabolic and alcoholic liver injuries result in nonalcoholic (NAFLD) or alcoholic (ALD) fatty liver disease, respectively. In particular, presence of fibrosis in NAFLD and ALD requires treatment, but development of drugs is hampered by the lack of suitable models with significant fibrosis. The carbon tetrachloride (CCl4) liver fibrosis model does not reflect human NAFLD or ALD, but CCl4 may serve as a fibrosis accelerator in addition to another injury. Ethanol in drinking water (16%) or Western diet (WD) were administered for 7 wk in mice either alone or in combination with CCl4 intoxications. Extent of fibrosis, steatosis, and inflammation was assessed by histology, transcription, and biochemistry. Furthermore, transcription of fibrosis, proliferation, and inflammation-related genes was studied on human liver samples with fibrosis resulting from hepatitis C virus infection (n = 7), NAFLD (n = 8), or ALD (n = 7). WD or ethanol alone induced only mild steatosis and inflammation. Combination of CCl4 and WD induced the most severe steatosis together with significant liver fibrosis and moderate inflammation. Combination of CCl4 and ethanol induced the strongest inflammation, with significant liver fibrosis and moderate steatosis. The relationship pattern between fibrosis, proliferation, and inflammation of human ALD was mostly similar in mice treated with CCl4 and ethanol. The combination of CCl4 intoxication with WD validates previous data suggesting it as an appropriate model for human nonalcoholic steatohepatitis. Especially, CCl4 plus ethanol for 7 wk induces ALD in mice, providing a model suitable for further basic research and drug testing. NEW & NOTEWORTHY Alcoholic fatty liver disease with significant fibrosis is generated within 7 wk using carbon tetrachloride as a fibrosis accelerator and administering gradually ethanol (up to 16%) in mice. The similarity in the pattern of steatosis, inflammation, and fibrosis involved in alcoholic fatty liver disease to those of the human condition renders this mouse model suitable as a preclinical model for drug development.

Keywords: ASH, Liver fibrosis, NAFLD, NASH


Torres-Sánchez, A., Vanegas, J. M., Purohit, P. K., Arroyo, M., (2019). Combined molecular/continuum modeling reveals the role of friction during fast unfolding of coiled-coil proteins Soft Matter 15, (24), 4961-4975

Coiled-coils are filamentous proteins that form the basic building block of important force-bearing cellular elements, such as intermediate filaments and myosin motors. In addition to their biological importance, coiled-coil proteins are increasingly used in new biomaterials including fibers, nanotubes, or hydrogels. Coiled-coils undergo a structural transition from an α-helical coil to an unfolded state upon extension, which allows them to sustain large strains and is critical for their biological function. By performing equilibrium and out-of-equilibrium all-atom molecular dynamics (MD) simulations of coiled-coils in explicit solvent, we show that two-state models based on Kramers' or Bell's theories fail to predict the rate of unfolding at high pulling rates. We further show that an atomistically informed continuum rod model accounting for phase transformations and for the hydrodynamic interactions with the solvent can reconcile two-state models with our MD results. Our results show that frictional forces, usually neglected in theories of fibrous protein unfolding, reduce the thermodynamic force acting on the interface, and thus control the dynamics of unfolding at different pulling rates. Our results may help interpret MD simulations at high pulling rates, and could be pertinent to cytoskeletal networks or protein-based artificial materials subjected to shocks or blasts.


Alvarez-Silva, C., Schierwagen, R., Pohlmann, A., Magdaleno, F., Uschner, F. E., Ryan, P., Vehreschild, M. J. G. T., Claria, J., Latz, E., Lelouvier, B., Arumugam, M., Trebicka, J., (2019). Compartmentalization of immune response and microbial translocation in decompensated cirrhosis Frontiers in Immunology 10, 69

Background: Acquired dysfunctional immunity in cirrhosis predisposes patients to frequent bacterial infections, especially spontaneous bacterial peritonitis (SBP), leading to systemic inflammation that is associated with poor outcome. But systemic inflammation can also be found in the absence of a confirmed infection. Detection of bacterial DNA has been investigated as a marker of SBP and as a predictor of prognosis. Data is, however, contradictory. Here we investigated whether levels of IL-6 and IL-8 putatively produced by myeloid cells in ascites are associated with systemic inflammation and whether inflammation depends on the presence of specific bacterial DNA. Methods and Materials: We enrolled 33 patients with decompensated liver cirrhosis from whom we collected paired samples of blood and ascites. IL-6 and IL-8 were measured in serum samples of all patients using ELISA. In a subset of 10 representative patients, bacterial DNA was extracted from ascites and whole blood, followed by 16S rRNA gene amplicon sequencing. Results: There were significantly higher levels of IL-6 in ascites fluid compared to blood samples in all patients. Interestingly, IL-6 levels in blood correlated tightly with disease severity and surrogates of systemic inflammation, while IL-6 levels in ascites did not. Moreover, patients with higher blood CRP levels showed greater SBP prevalence compared to patients with lower levels, despite similar positive culture results. Bacterial richness was also significantly higher in ascites compared to the corresponding patient blood. We identified differences in microbial composition and diversity between ascites and blood, but no tight relationship with surrogates of systemic inflammation could be observed. Discussion: In decompensated cirrhosis, markers of systemic inflammation and microbiota composition seem to be dysregulated in ascites and blood. While a relationship between systemic inflammation and microbiota composition seems to exist in blood, this is not the case for ascites in our hands. These data may suggest compartmentalization of the immune response and interaction of the latter with the microbiota especially in the blood compartment.

Keywords: Acute-on-chronic liver failure, Ascites, Cirrhosis, Cytokines, Microbiome, Myeloid cells, Systemic inflammation


Bortolla, Roberta, Cavicchioli, Marco, Galli, Marco, Verschure, P., Maffei, Cesare, (2019). A comprehensive evaluation of emotional responsiveness in borderline personality disorder: a support for hypersensitivity hypothesis Borderline Personality Disorder and Emotion Dysregulation 6, (1), 8

Background: Many experimental studies have evaluated Linehan’s biological emotional vulnerability in Borderline Personality Disorder (BPD). However, some inconsistencies were observed in operationalizing and supporting its components. This study aims at clarifying which aspects of Linehan’s model are altered in BPD, considering a multimodal evaluation of processes concerned with emotional responsiveness (self-report, psychophysiology and eye-tracking). Methods: Forty-eight socio-emotional pictures were administered to 28 participants (14 BPD, 14 Healthy Controls, HCs), gender- and age-matched, by employing two different lengths of stimuli exposure (5 s and 15 s). Results: Our results supported the hypersensitivity hypothesis in terms of faster physiological responses and altered visual processing. Furthermore, hypersensitivity was associated with detailed socio-emotional contents. Hyperreactivity assumption was not experimentally sustained by physiological and self-report data. Ultimately, the slow return to emotional baseline was demonstrated as an impaired emotional modulation. Conclusions: Our data alternatively supported the hypersensitivity and the slow return to emotional baseline hypotheses, postulated by Linehan’s Biosocial model, rather than the hyperreactivity assumption. Results have been discussed in light of other BPD core psychopathological processes.

Keywords: Borderline personality disorder, Emotional vulnerability, Linehan’s model, Hypersensitivity, Slow return to emotional baseline


Fraioli, R., Neubauer, S., Rechenmacher, F., Bosch, B. M., Dashnyam, K., Kim, J. H., Perez, R. A., Kim, H. W., Gil, F. J., Ginebra, M. P., Manero, J. M., Kessler, H., Mas-Moruno, C., (2019). Control of stem cell response and bone growth on biomaterials by fully non-peptidic integrin selective ligands Biomaterials Science 7, (4), 1281-1285

In this communication we report that anchoring αvβ3 or α5β1 integrin-selective RGD peptidomimetics to titanium efficiently tunes mesenchymal stem cell response in vitro and bone growth in rat calvarial defects. Our results demonstrate that this molecular chemistry-derived approach could be successful to engineer instructive coatings for orthopedic applications.


Tahirbegi, I. B., Pérez, Y., Mir, M., Samitier, J., (2019). Counterions effect on uracil-silver coordination Inorganica Chimica Acta 490, 246-253

Cyanide based silver electroplating is a low-cost reliable and well-established process for metal deposition. However, delicate handling during the process is needed because of the high toxicity of cyanide, for the persons and the environment. Uracil based silver electrodeposition got the attention of this field, because of its low cost and non-toxic nature. However, little is known about the silver complexation with uracil and the process behind the silver electroplating. In this work, we studied a hitherto unknown phenomenon on the diverse structure’s formation of silver uracil coordination complex due to the presence of different alkaline counterions. The distinct structuration of this complex clearly impacts on the efficiency and deposition yields of silver electroplating. We demonstrate the unknown key role that play hydroxide counterions in the uracil-silver coordination, and the different molecular structures created on the basis of the used counterion. The hydroxide counterion determines monomeric and polymeric complex formation with silver, which affects the solubility of the uracil silver complex and its subsequent electrodeposition. The different molecular complexes were characterized by FT-IR, UV–vis, DRUV–vis and multi-nuclear NMR spectroscopy and the silver electrodeposition by cyclic voltammetry and TOF-SIMS. This study sheds some light in the improvement of silver electroplating process

Keywords: Coordination complex, Electrometallization, Electroplating, Metal complex, Silver electrodeposition, Uracil


Aguiar, L., Biosca, A., Lantero, E., Gut, J., Vale, N., Rosenthal, P. J., Nogueira, F., Andreu, D., Fernàndez-Busquets, X., Gomes, P., (2019). Coupling the antimalarial cell penetrating peptide TP10 to classical antimalarial drugs primaquine and chloroquine produces strongly hemolytic conjugates Molecules 24, (24), 4559

Recently, we disclosed primaquine cell penetrating peptide conjugates that were more potent than parent primaquine against liver stage Plasmodium parasites and non-toxic to hepatocytes. The same strategy was now applied to the blood-stage antimalarial chloroquine, using a wide set of peptides, including TP10, a cell penetrating peptide with intrinsic antiplasmodial activity. Chloroquine-TP10 conjugates displaying higher antiplasmodial activity than the parent TP10 peptide were identified, at the cost of an increased hemolytic activity, which was further confirmed for their primaquine analogues. Fluorescence microscopy and flow cytometry suggest that these drug-peptide conjugates strongly bind, and likely destroy, erythrocyte membranes. Taken together, the results herein reported put forward that coupling antimalarial aminoquinolines to cell penetrating peptides delivers hemolytic conjugates. Hence, despite their widely reported advantages as carriers for many different types of cargo, from small drugs to biomacromolecules, cell penetrating peptides seem unsuitable for safe intracellular delivery of antimalarial aminoquinolines due to hemolysis issues. This highlights the relevance of paying attention to hemolytic effects of cell penetrating peptide-drug conjugates.

Keywords: Antimalarial, Cell penetrating peptide, Chloroquine, Erythrocyte fluorescence, Flow cytometry, Hemolysis, Microscopy, Plasmodium, Primaquine, Red blood cell


Ballester, B. R., Maier, M., Duff, A., Cameirão, M., Bermúdez, S., Duarte, E., Cuxart, A., Rodríguez, S., San Segundo Mozo, R. M., Verschure, P., (2019). A critical time window for recovery extends beyond one-year post-stroke Journal of neurophysiology 122, (1), 350-357

The impact of rehabilitation on post-stroke motor recovery and its dependency on the patient's chronicity remain unclear. The field has widely accepted the notion of a proportional recovery rule with a "critical window for recovery" within the first 3-6 mo poststroke. This hypothesis justifies the general cessation of physical therapy at chronic stages. However, the limits of this critical window have, so far, been poorly defined. In this analysis, we address this question, and we further explore the temporal structure of motor recovery using individual patient data from a homogeneous sample of 219 individuals with mild to moderate upper-limb hemiparesis. We observed that improvement in body function and structure was possible even at late chronic stages. A bootstrapping analysis revealed a gradient of enhanced sensitivity to treatment that extended beyond 12 mo poststroke. Clinical guidelines for rehabilitation should be revised in the context of this temporal structure. NEW & NOTEWORTHY Previous studies in humans suggest that there is a 3- to 6-mo "critical window" of heightened neuroplasticity poststroke. We analyze the temporal structure of recovery in patients with hemiparesis and uncover a precise gradient of enhanced sensitivity to treatment that expands far beyond the limits of the so-called critical window. These findings highlight the need for providing therapy to patients at the chronic and late chronic stages.

Keywords: Motor recovery, Neuroplasticity, Neurorehabilitation, Stroke recovery, Virtual reality


De Matteis, Valeria, Rizzello, Loris, Ingrosso, Chiara, Liatsi-Douvitsa, Eva, De Giorgi, Maria Luisa, De Matteis, Giovanni, Rinaldi, Rosaria, (2019). Cultivar-dependent anticancer and antibacterial properties of silver nanoparticles synthesized using leaves of different Olea Europaea trees Nanomaterials 9, (11), 1544

The green synthesis of nanoparticles (NPs) is currently under worldwide investigation as an eco-friendly alternative to traditional routes (NPs): the absence of toxic solvents and catalysts make it suitable in the design of promising nanomaterials for nanomedicine applications. In this work, we used the extracts collected from leaves of two cultivars (Leccino and Carolea) belonging to the species Olea Europaea, to synthesize silver NPs (AgNPs) in different pH conditions and low temperature. NPs underwent full morphological characterization with the aim to define a suitable protocol to obtain a monodispersed population of AgNPs. Afterwards, to validate the reproducibility of the mentioned synthetic procedure, we moved on to another Mediterranean plant, the Laurus Nobilis. Interestingly, the NPs obtained using the two olive cultivars produced NPs with different shape and size, strictly depending on the cultivar selected and pH. Furthermore, the potential ability to inhibit the growth of two woman cancer cells (breast adenocarcinoma cells, MCF-7 and human cervical epithelioid carcinoma, HeLa) were assessed for these AgNPs, as well as their capability to mitigate the bacteria concentration in samples of contaminated well water. Our results showed that toxicity was stronger when MCF-7 and Hela cells were exposed to AgNPs derived from Carolea obtained at pH 7 presenting irregular shape; on the other hand, greater antibacterial effect was revealed using AgNPs obtained at pH 8 (smaller and monodispersed) on well water, enriched with bacteria and coliforms.

Keywords: Green synthesis, Silver nanoparticles, Olea Europaea, Leccino, Carolea, Cytotoxicity, Genotoxicity, Antibacterial activity


Montero, Joan, Gstalder, Cécile, Kim, Daniel J., Sadowicz, Dorota, Miles, Wayne, Manos, Michael, Cidado, Justin R., Paul Secrist, J., Tron, Adriana E., Flaherty, Keith, Stephen Hodi, F., Yoon, Charles H., Letai, Anthony, Fisher, David E., Haq, Rizwan, (2019). Destabilization of NOXA mRNA as a common resistance mechanism to targeted therapies Nature Communications 10, (1), 5157

Most targeted cancer therapies fail to achieve complete tumor regressions or attain durable remissions. To understand why these treatments fail to induce robust cytotoxic responses despite appropriately targeting oncogenic drivers, here we systematically interrogated the dependence of cancer cells on the BCL-2 family of apoptotic proteins after drug treatment. We observe that multiple targeted therapies, including BRAF or EGFR inhibitors, rapidly deplete the pro-apoptotic factor NOXA, thus creating a dependence on the anti-apoptotic protein MCL-1. This adaptation requires a pathway leading to destabilization of the NOXA mRNA transcript. We find that interruption of this mechanism of anti-apoptotic adaptive resistance dramatically increases cytotoxic responses in cell lines and a murine melanoma model. These results identify NOXA mRNA destabilization/MCL-1 adaptation as a non-genomic mechanism that limits apoptotic responses, suggesting that sequencing of MCL-1 inhibitors with targeted therapies could overcome such widespread and clinically important resistance.

Keywords: Cancer therapeutic resistance, Melanoma, Targeted therapies


Klein, L. M., Chang, J., Gu, W., Manekeller, S., Jansen, C., Lingohr, P., Praktiknjo, M., Kalf, J. C., Schulz, M., Spengler, U., Strassburg, C., Cárdenas, A., Arroyo, V., Trebicka, J., (2019). The Development and Outcome of Acute-on-Chronic Liver Failure After Surgical Interventions Liver Transplantation Early View,

Acute-on-chronic liver failure (ACLF) is a syndrome with high short-term mortality. Precipitating events, including hemorrhage and infections, contribute to ACLF development, but the role of surgery remains unknown. We investigated the development of ACLF in patients with cirrhosis undergoing surgery. In total, 369 patients with cirrhosis were included in the study. The clinical and laboratory data were collected prior to and on days 1-2, 3-8, and 9-28, and at 3 and 12 months after surgery. Surgery type was classified as limited or extensive, as well as liver and nonliver surgery. A total of 39 patients had baseline ACLF. Surgery was performed during acute decompensation in 35% of the rest of the 330 patients, and 81 (24.5%) developed ACLF within 28 days after surgery. Surrogate markers of systemic inflammation were similar in patients who developed ACLF or not. Age, sex, serum sodium, baseline bacterial infection, and abdominal nonliver surgery were independent predictors for the development of ACLF after surgery. Patients who developed ACLF within 28 days after surgery had a higher mortality at 3, 6, and 12 months. Survival did not differ between patients with ACLF at surgery and those developing ACLF after surgery. Development of ACLF within 28 days after surgery and elevated alkaline phosphatase and international normalized ratio were independent predictors of 90-day mortality. Independent predictors of 1-year all‐cause mortality were alkaline phosphatase, Model for End-Stage Liver Disease score, and preoperative hepatic encephalopathy, whereas nonliver surgery was associated with improved survival. ACLF frequently develops in patients with cirrhosis undergoing surgery, especially in those with active bacterial infection, lower serum sodium, and kidney or coagulation dysfunction. Prognoses of ACLF both at and after surgery are similarly poor. Patients with cirrhosis should be carefully managed perioperatively.


Rey-Vinolas, S., Castaño, O., Ruiz-Macarrilla, L., Llorens, X., Mora, J. M., Engel, E., Mateos-Timoneda, M. A., (2019). Development of a novel automatable fabrication method based on electrospinning co electrospraying for rotator cuff augmentation patches PLoS ONE 14, (11), e0224661

Rotator cuff tear is one of the most common shoulder diseases. Rotator cuff augmentation (RCA) is trying to solve the high retear failure percentage after the surgery procedures (20–90%). The ideal augmentation patch must provide a temporal mechanical support during the healing process. In this work, we proposed a simple method for the fabrication of synthetic RCA patches. This method combines the use of electrospraying to produce poly-L-lactic-co-ε-caprolactone (PLC) films in an organogel form and electrospinning to produce poly(lactic) acid (PLA) nanofibers. The device consists in a combination of layers, creating a multilayered construct, enabling the possibility of tuning its mechanical properties and thickness. Besides, both techniques are simple to escalate for industrial production. A complete characterization has been performed to optimize the involved number of layers and production time of PLC films and PLA nanofibers fabrication, obtaining a final optimal configuration for RCA devices. Structural, mechanical and suture properties were evaluated. Also, the possibility of surface functionalization to improve the bioactivity of the scaffold was studied, adding aligned electrospun PLA nanofibers on the surface of the device to mimic the natural tendon topography. Surface modification was characterized by culturing adult normal human dermal fibroblasts. Lack of toxicity was detected for material presented, and cell alignment shape orientation guided by aligned fibers, mimicking tendon structure, was obtained. Cell proliferation and protein production were also evaluated.


Cofiño, C., Perez-Amodio, S., Semino, C. E., Engel, E., Mateos-Timoneda, M. A., (2019). Development of a self-assembled peptide/methylcellulose-based bioink for 3D bioprinting Macromolecular Materials and Engineering 304, (11), 1900353

The introduction of 3D bioprinting to fabricate living constructs with tailored architecture has provided a new paradigm for biofabrication, with the potential to overcome several drawbacks of conventional scaffold-based tissue regeneration strategies. Hydrogel-based materials are suitable candidates regarding cell biocompatibility but often display poor mechanical properties. Self-assembling peptides are a promising source of biomaterials to be used as 3D scaffolds based on their similarity to extracellular matrices (structurally and mechanically). In this study, an advanced bioink for biofabrication is presented based on the optimization of a RAD16-I-based biomaterial. The strategy followed to build 3D predefined structures by 3D printing is based on an enhancement of bioink viscosity by adding methylcellulose (MC) to a RAD16-I solution. The resultant constructs display high shape fidelity and stability and embedded human mesenchymal stem cells present high viability after 7 days of culture. Moreover, cells are also able to differentiate to the adipogenic lineage, suggesting the suitability of this novel biomaterial for soft tissue engineering applications.

Keywords: 3D bioprinting, Biofabrication, Bioinks, Self-assembling peptides, Tissue engineering


Campillo, N., Falcones, B., Otero, J., Colina, R., Gozal, D., Navajas, D., Farré, R., Almendros, I., (2019). Differential oxygenation in tumor microenvironment modulates macrophage and cancer cell crosstalk: Novel experimental settingand proof of concept Frontiers in Oncology 9, 43

Hypoxia is a common characteristic of many solid tumors that has been associated with tumor aggressiveness. Limited diffusion of oxygen generates a gradient of oxygen availability from the blood vessel to the interstitial space and may underlie the recruitment of macrophages fostering cancer progression. However, the available data based on the recruitment of circulating cells to the tumor microenvironment has been so far carried out by conventional co-culture systems which ignore the hypoxic gradient between the vessel to the tumor interstitium. Here, we have designed a novel easy-to-build cell culture device that enables evaluation of cellular cross-talk and cell migration while they are being simultaneously exposed to different oxygenation environments. As a proof-of-concept of the potential role of differential oxygenation among interacting cells we have evaluated the activation and recruitment of macrophages in response to hypoxic melanoma, breast, and kidney cancer cells. We found that hypoxic melanoma and breast cancer cells co-cultured with normoxic macrophages enhanced their directional migration. By contrast, hypoxic kidney cells were not able to increase their recruitment. We also identified well-described hypoxia-induced pathways which could contribute in the immune cell recruitment (VEGFA and PTGS2 genes). Moreover, melanoma and breast cancer increased their proliferation. However, oxygenation levels affected neither kidney cancer cell proliferation nor gene expression, which in turn resulted in no significant changes in macrophage migration and polarization. Therefore, the cell culture device presented here provides an excellent opportunity for researchers to reproduce the in vivo hypoxic gradients in solid tumors and to study their role in recruiting circulating cells to the tumor in specific types of cancer.

Keywords: Hypoxia gradient, Macrophage motility, Models of host-tumor interactions, Novel assay technology, Tumor progression


Park, D. E., Cheng, J., Berrios, C., Montero, J., Cortés-Cros, M., Ferretti, S., Arora, R., Tillgren, M. L., Gokhale, P. C., DeCaprio, J. A., (2019). Dual inhibition of MDM2 and MDM4 in virus-positive Merkel cell carcinoma enhances the p53 response Proceedings of the National Academy of Sciences of the United States of America 116, (3), 1027-1032

Merkel cell polyomavirus (MCV) contributes to approximately 80% of all Merkel cell carcinomas (MCCs), a highly aggressive neuroendocrine carcinoma of the skin. MCV-positive MCC expresses small T antigen (ST) and a truncated form of large T antigen (LT) and usually contains wild-type p53 (TP53) and RB (RB1). In contrast, virus-negative MCC contains inactivating mutations in TP53 and RB1. While the MCV-truncated LT can bind and inhibit RB, it does not bind p53. We report here that MCV LT binds to RB, leading to increased levels of ARF, an inhibitor of MDM2, and activation of p53. However, coexpression of ST reduced p53 activation. MCV ST recruits the MYC homologue MYCL (L-Myc) to the EP400 chromatin remodeler complex and transactivates specific target genes. We observed that depletion of EP400 in MCV-positive MCC cell lines led to increased p53 target gene expression. We suspected that the MCV ST–MYCL–EP400 complex could functionally inactivate p53, but the underlying mechanism was not known. Integrated ChIP and RNA-sequencing analysis following EP400 depletion identified MDM2 as well as CK1α, an activator of MDM4, as target genes of the ST–MYCL–EP400 complex. In addition, MCV-positive MCC cells expressed high levels of MDM4. Combining MDM2 inhibitors with lenalidomide targeting CK1α or an MDM4 inhibitor caused synergistic activation of p53, leading to an apoptotic response in MCV-positive MCC cells and MCC-derived xenografts in mice. These results support dual targeting of MDM2 and MDM4 in virus-positive MCC and other p53 wild-type tumors.

Keywords: Casein kinase 1 alpha, Lenalidomide, MDM2-MDM4, Merkel cell carcinoma, P53


Montero, J., (2019). Dual oncogene excision is greater than the sum of its parts Science Translational Medicine 11, (491), eaax4876

Ablation of EGFR and c-RAF in combination is effective against aggressive pancreatic tumors.


Malandrino, Andrea, Trepat, Xavier, Kamm, Roger D., Mak, Michael, (2019). Dynamic filopodial forces induce accumulation, damage, and plastic remodeling of 3D extracellular matrices PLoS Computational Biology PLOS Computational Biology , 15, (4), e1006684

The mechanical properties of the extracellular matrix (ECM)–a complex, 3D, fibrillar scaffold of cells in physiological environments–modulate cell behavior and can drive tissue morphogenesis, regeneration, and disease progression. For simplicity, it is often convenient to assume these properties to be time-invariant. In living systems, however, cells dynamically remodel the ECM and create time-dependent local microenvironments. Here, we show how cell-generated contractile forces produce substantial irreversible changes to the density and architecture of physiologically relevant ECMs–collagen I and fibrin–in a matter of minutes. We measure the 3D deformation profiles of the ECM surrounding cancer and endothelial cells during stages when force generation is active or inactive. We further correlate these ECM measurements to both discrete fiber simulations that incorporate fiber crosslink unbinding kinetics and continuum-scale simulations that account for viscoplastic and damage features. Our findings further confirm that plasticity, as a mechanical law to capture remodeling in these networks, is fundamentally tied to material damage via force-driven unbinding of fiber crosslinks. These results characterize in a multiscale manner the dynamic nature of the mechanical environment of physiologically mimicking cell-in-gel systems.

Keywords: Collagens, Fibrin, Extracellular matrix, Cross-linking, Cell physiology, Deformation, Fluorescence imaging, Cell biology


Farré, R., Montserrat, J. M., Solana, G., Gozal, D., Navajas, D., (2019). Easy-to-build and affordable continuous positive airway pressure CPAP device for adult patients in low-income countries European Respiratory Journal 53, (5), 1802290

Continuous positive airway pressure (CPAP) is the treatment of choice for several types of sleep disordered breathing (SDB), of which sleep apnoea is an obvious example. Although precise epidemiological data are scarce, SDB are prevalent in low-income countries (LICs). Moreover, given that the risk of SDB is associated with the patient's body mass index, and that the worldwide obesity pandemic involves not only developed countries but also LICs, it is expected that the incidence of sleep apnoea will continuously increase in LICs, and the need for CPAP devices will accordingly rise. Moreover, the demand for CPAP devices in LICs is also anticipated to increase in light of the few operationally equipped intensive care units in these countries. Indeed, cheap CPAP devices, although with less versatile applications than mechanical ventilators, provide rescue and treatment options that can reduce mortality and intubation rates in some patients. Unfortunately, these options are seldom implemented in LICs since neither patients nor hospitals are able to afford commercial CPAP devices. It is also noteworthy that CPAP devices specifically designed and commercialised in LICs, which achieve cost reductions by avoiding optional device features, do not offer a realistic therapeutic alternative.


Jansen, C., Trebicka, J., (2019). Editorial: diastolic dysfunction seems not to be decisive for survival after transjugular intrahepatic portosystemic stent-shunt Alimentary pharmacology & therapeutics 49, (8), 1101-1102

Armstrong et al take a closer look at cardiac diagnostics in patients evaluated for transjugular intrahepatic portosystemic stent-shunt (TIPSS) insertion. Although highly selected in their patients, presence of diastolic dysfunction was not associated with survival, but Model for End-Stage Liver Disease (MELD) score remained the best predictor of survival. The clinical “gut-feeling” and pathophysiological understanding suggest that the cardiac function should play a role and should be investigated prior to TIPSS insertion in these patients. Therefore, the question arises, is echocardiography relevant for selection of patients to TIPSS and if yes what parameters are the relevant ones?


Sadowska, J. M., Wei, F., Guo, J., Guillem-Marti, J., Lin, Z., Ginebra, M. P., Xiao, Y., (2019). The effect of biomimetic calcium deficient hydroxyapatite and sintered β-tricalcium phosphate on osteoimmune reaction and osteogenesis Acta Biomaterialia 96, 605-618

Biomaterial implantation triggers inflammatory reactions. Understanding the effect of physicochemical features of biomaterials on the release of inflammatory cytokines from immune cells would be of great interest in view of designing bone graft materials to enhance the healing of bone defects. The present work investigated the interactions of two chemically and texturally different calcium phosphate (CaPs) substrates with macrophages, one of the main innate immune cells, and its further impact on osteogenic differentiation of bone forming cells. The behaviour of macrophages seeded on biomimetic calcium deficient hydroxyapatite (CDHA) and sintered β-tricalcium phosphate (β-TCP) was assessed in terms of the release of inflammatory cytokines and osteoclastogenic factors. The osteogenic differentiation of bone progenitor cells (bone marrow stromal cells (BMSCs) and osteoblastic cell line (SaOS-2)) were subsequently studied by incubating with the conditioned medium induced by macrophage-CaPs interaction in order to reveal the effect of immune cell reaction to CaPs on osteogenic differentiation. It was found that the incubation of macrophages with CaPs substrates caused a decrease of pro-inflammatory cytokines, more pronounced for β-TCP compared with CDHA showing significantly decreased IL-6, TNF-a, and iNOS. However, the macrophage-CDHA interaction resulted in a more favourable environment for osteogenic differentiation of osteoblasts with more collagen type I production and osteogenic genes (Runx2, BSP) expression, suggesting that osteogenic differentiation of bone cells is not only determined by the nature of biomaterials, but also significantly influenced by the inflammatory environment generated by the interaction of immune cells and biomaterials. Statement of Significance: The field of osteoimmunology highlights the importance of the cross-talk between immune and bone cells for effective bone regeneration. This tight interaction opens the door to new strategies that encompass the development of smart cell-instructive biomaterials which performance covers the events from early inflammation to osteogenesis. The present work links the anti-inflammatory and osteoimmunomodulatory features of synthetic bone grafts to their chemistry and texture, focussing on the cross-talk between macrophages and two major orchestrators of bone healing, namely primary mesenchymal stem cells and osteoblasts. The results emphasize the importance of the microenvironment created through the interaction between the substrate and the immune cells as it can stimulate osteogenic events and subsequently foster bone healing.

Keywords: Calcium phosphates, Immunomodulation, Inflammation, Osteogenesis, Osteoimmunomodulation


Diez-Escudero, A., Torreggiani, E., Di Pompo, G., Espanol, M., Persson, C., Ciapetti, G., Baldini, N., Ginebra, M. P., (2019). Effect of calcium phosphate heparinization on the in vitro inflammatory response and osteoclastogenesis of human blood precursor cells Journal of Tissue Engineering and Regenerative Medicine 13, (7), 1217-1229

The immobilization of natural molecules on synthetic bone grafts stands as a strategy to enhance their biological interactions. During the early stages of healing, immune cells and osteoclasts (OC) modulate the inflammatory response and resorb the biomaterial, respectively. In this study, heparin, a naturally occurring molecule in the bone extracellular matrix, was covalently immobilized on biomimetic calcium‐deficient hydroxyapatite (CDHA). The effect of heparin‐functionalized CDHA on inflammation and osteoclastogenesis was investigated using primary human cells and compared with pristine CDHA and beta-tricalcium phosphate (β-TCP). Biomimetic substrates led to lower oxidative stresses by neutrophils and monocytes than sintered β-TCP, even though no further reduction was induced by the presence of heparin. In contrast, heparinized CDHA fostered osteoclastogenesis. Optical images of stained TRAP positive cells showed an earlier and higher presence of multinucleated cells, compatible with OC at 14 days, while pristine CDHA and β-TCP present OC at 21–28 days. Although no statistically significant differences were found in the OC activity, microscopy images evidenced early stages of degradation on heparinized CDHA, compatible with osteoclastic resorption. Overall, the results suggest that the functionalization with heparin fostered the formation and activity of OC, thus offering a promising strategy to integrate biomaterials in the bone remodelling cycle by increasing their OC-mediated resorption.

Keywords: Biomaterial, Heparin, Hydroxyapatite, Inflammation, Osteoclastogenesis


Maier, Martina, Rubio Ballester, Belén, Duff, Armin, Duarte Oller, Esther, Verschure, P., (2019). Effect of specific over nonspecific VR-based rehabilitation on poststroke motor recovery: A systematic meta-analysis Neurorehabilitation and Neural Repair 33, (2), 112-129

Background. Despite the rise of virtual reality (VR)-based interventions in stroke rehabilitation over the past decade, no consensus has been reached on its efficacy. This ostensibly puzzling outcome might not be that surprising given that VR is intrinsically neutral to its use—that is, an intervention is effective because of its ability to mobilize recovery mechanisms, not its technology. As VR systems specifically built for rehabilitation might capitalize better on the advantages of technology to implement neuroscientifically grounded protocols, they might be more effective than those designed for recreational gaming. Objective. We evaluate the efficacy of specific VR (SVR) and nonspecific VR (NSVR) systems for rehabilitating upper-limb function and activity after stroke. Methods. We conducted a systematic search for randomized controlled trials with adult stroke patients to analyze the effect of SVR or NSVR systems versus conventional therapy (CT). Results. We identified 30 studies including 1473 patients. SVR showed a significant impact on body function (standardized mean difference [SMD] = 0.23; 95% CI = 0.10 to 0.36; P = .0007) versus CT, whereas NSVR did not (SMD = 0.16; 95% CI = −0.14 to 0.47; P = .30). This result was replicated in activity measures. Conclusions. Our results suggest that SVR systems are more beneficial than CT for upper-limb recovery, whereas NSVR systems are not. Additionally, we identified 6 principles of neurorehabilitation that are shared across SVR systems and are possibly responsible for their positive effect. These findings may disambiguate the contradictory results found in the current literature.

Keywords: Stroke, Paresis, Virtual reality, Rehabilitation, Occupational therapy, Review


Lopez-Martinez, Montserrat, López-Ortiz, Manuel, Antinori, Maria Elena, Wientjes, Emilie, Nin-Hill, Alba, Rovira, Carme, Croce, Roberta, Díez-Pérez, Ismael, Gorostiza, Pau, (2019). Electrochemically gated long distance charge transport in photosystem I Angewandte Chemie International Edition 58, (38), 13280-13284

The transport of electrons along photosynthetic and respiratory chains involves a series of enzymatic reactions that are coupled through redox mediators, including proteins and small molecules. The use of native and synthetic redox probes is key to understand charge transport mechanisms, and to design bioelectronic sensors and solar energy conversion devices. However, redox probes have limited tunability to exchange charge at the desired electrochemical potentials (energy levels) and at different protein sites. Here, we take advantage of electrochemical scanning tunneling microscopy (ECSTM) to control the Fermi level and nanometric position of the ECSTM probe in order to study electron transport in individual photosystem I (PSI) complexes. Current-distance measurements at different potentiostatic conditions indicate that PSI supports long-distance transport that is electrochemically gated near the redox potential of P700, with current extending farther under hole injection conditions.

Keywords: Current decay, ECSTM, Electrochemical gate, Electron transfer, Photosynthesis


Sarlabous, L., Estrada, L., Cerezo-Hernández, A., Leest, Sietske V. D., Torres, A., Jané, R., Duiverman, M., Garde, Ainara, (2019). Electromyography-based respiratory onset detection in COPD patients on non-invasive mechanical ventilation Entropy 21, (3), 258

To optimize long-term nocturnal non-invasive ventilation in patients with chronic obstructive pulmonary disease, surface diaphragm electromyography (EMGdi) might be helpful to detect patient-ventilator asynchrony. However, visual analysis is labor-intensive and EMGdi is heavily corrupted by electrocardiographic (ECG) activity. Therefore, we developed an automatic method to detect inspiratory onset from EMGdi envelope using fixed sample entropy (fSE) and a dynamic threshold based on kernel density estimation (KDE). Moreover, we combined fSE with adaptive filtering techniques to reduce ECG interference and improve onset detection. The performance of EMGdi envelopes extracted by applying fSE and fSE with adaptive filtering was compared to the root mean square (RMS)-based envelope provided by the EMG acquisition device. Automatic onset detection accuracy, using these three envelopes, was evaluated through the root mean square error (RMSE) between the automatic and mean visual onsets (made by two observers). The fSE-based method provided lower RMSE, which was reduced from 298 ms to 264 ms when combined with adaptive filtering, compared to 301 ms provided by the RMS-based method. The RMSE was negatively correlated with the proposed EMGdi quality indices. Following further validation, fSE with KDE, combined with adaptive filtering when dealing with low quality EMGdi, indicates promise for detecting the neural onset of respiratory drive.

Keywords: Fixed sample entropy, Adaptive filtering, Root mean square, Diaphragm electromyography, Non-invasive mechanical ventilation, Chronic obstructive pulmonary disease


Bertuoli, Paula T., Ordoño, Jesús, Armelin, Elaine, Pérez-Amodio, Soledad, Baldissera, Alessandra F., Ferreira, Carlos A., Puiggalí, Jordi, Engel, Elisabeth, del Valle, Luis J., Alemán, Carlos, (2019). Electrospun conducting and biocompatible uniaxial and core–shell fibers having poly(lactic acid), poly(ethylene glycol), and polyaniline for cardiac tissue engineering ACS Omega 4, (2), 3660-3672

Electroactive and biocompatible fibrous scaffolds have been prepared and characterized using polyaniline (PAni) doped with dodecylbenzenesulfonic acid (DBSA) combined with poly(lactic acid) (PLA) and PLA/poly(ethylene glycol) (PEG) mixtures. The composition of simple and core–shell fibers, which have been obtained by both uniaxial and coaxial electrospinning, respectively, has been corroborated by Fourier-transform infrared and micro-Raman spectroscopies. Morphological studies suggest that the incorporation of PEG enhances the packing of PLA and PAni chains, allowing the regulation of the thickness of the fibers. PAni and PEG affect the thermal and electrical properties of the fibers, both decreasing the glass transition temperature and increasing the electrical conductivity. Interestingly, the incorporation of PEG improves the PAni-containing paths associated with the conduction properties. Although dose response curves evidence the high cytotoxicity of PAni/DBSA, cell adhesion and cell proliferation studies on PLA/PAni fibers show a reduction of such harmful effects as the conducting polymer is mainly retained inside the fibers through favorable PAni···PLA interactions. The incorporation of PEG into uniaxial fibers resulted in an increment of the cell mortality, which has been attributed to its rapid dissolution into the culture medium and the consequent enhancement of PAni release. In opposition, the delivery of PAni decreases and, therefore, the biocompatibility of the fibers increases when a shell coating the PAni-containing system is incorporated through coaxial electrospinning. Finally, morphological and functional studies using cardiac cells indicated that these fibrous scaffolds are suitable for cardiac tissue engineering applications.


Arroyo, M., Trepat, X., (2019). Embryonic self-fracking Science 365, (6452), 442-443

From a broken bone to a major earthquake, the fracture of a material usually means trouble. However, in some practical applications engineers have learned how to harness the mechanisms of fracture. This is illustrated by the well-known process of hydraulic fracturing, or “fracking,” in which injection of pressurized fluid in shale rocks opens cracks to extract oil or gas (1). On page 465 of this issue, Dumortier et al. (2) show that the developing mouse embryo uses this same principle to transiently disrupt its shape and sculpt a more complex one. Fracking is the key mechanism that enables the early embryo to develop its first symmetry axis, a key stage in fetal morphogenesis.


Valls-Margarit, M., Iglesias-García, O., Di Guglielmo, C., Sarlabous, L., Tadevosyan, K., Paoli, R., Comelles, J., Blanco-Almazán, D., Jiménez-Delgado, S., Castillo-Fernández, O., Samitier, J., Jané, R., Martínez, E., Raya, Á., (2019). Engineered macroscale cardiac constructs elicit human myocardial tissue-like functionality Stem Cell Reports 13, (1), 207-220

In vitro surrogate models of human cardiac tissue hold great promise in disease modeling, cardiotoxicity testing, and future applications in regenerative medicine. However, the generation of engineered human cardiac constructs with tissue-like functionality is currently thwarted by difficulties in achieving efficient maturation at the cellular and/or tissular level. Here, we report on the design and implementation of a platform for the production of engineered cardiac macrotissues from human pluripotent stem cells (PSCs), which we term “CardioSlice.” PSC-derived cardiomyocytes, together with human fibroblasts, are seeded into large 3D porous scaffolds and cultured using a parallelized perfusion bioreactor with custom-made culture chambers. Continuous electrical stimulation for 2 weeks promotes cardiomyocyte alignment and synchronization, and the emergence of cardiac tissue-like properties. These include electrocardiogram-like signals that can be readily measured on the surface of CardioSlice constructs, and a response to proarrhythmic drugs that is predictive of their effect in human patients.

Keywords: Cardiac tissue engineering, CardioSlice, ECG-like signals, Electrical stimulation, Heart physiology, Human induced pluripotent stem cells, Perfusion bioreactor, Tissue-like properties


Castillo-Escario, Y., Ferrer-Lluis, I., Montserrat, J. M., Jané, R., (2019). Entropy analysis of acoustic signals recorded with a smartphone for detecting apneas and hypopneas: A comparison with a commercial system for home sleep apnea diagnosis IEEE Access 7, 128224-128241

Obstructive sleep apnea (OSA) is a prevalent disease, but most patients remain undiagnosed and untreated. Here we propose analyzing smartphone audio signals for screening OSA patients at home. Our objectives were to: (1) develop an algorithm for detecting silence events and classifying them into apneas or hypopneas; (2) evaluate the performance of this system; and (3) compare the information provided with a type 3 portable sleep monitor, based mainly on nasal airflow. Overnight signals were acquired simultaneously by both systems in 13 subjects (3 healthy subjects and 10 OSA patients). The sample entropy of audio signals was used to identify apnea/hypopnea events. The apnea-hypopnea indices predicted by the two systems presented a very high degree of concordance and the smartphone correctly detected and stratified all the OSA patients. An event-by-event comparison demonstrated good agreement between silence events and apnea/hypopnea events in the reference system (Sensitivity = 76%, Positive Predictive Value = 82%). Most apneas were detected (89%), but not so many hypopneas (61%). We observed that many hypopneas were accompanied by snoring, so there was no sound reduction. The apnea/hypopnea classification accuracy was 70%, but most discrepancies resulted from the inability of the nasal cannula of the reference device to record oral breathing. We provided a spectral characterization of oral and nasal breathing to correct this effect, and the classification accuracy increased to 82%. This novel knowledge from acoustic signals may be of great interest for clinical practice to develop new non-invasive techniques for screening and monitoring OSA patients at home.

Keywords: Sleep apnea, Acoustics, Monitoring, Entropy, Sensors, Microphones, Acoustics, Biomedical signal processing, mHealth, Monitoring, Sleep apnea, Smartphone


Llopis-Lorente, A., Garcií-Fernández, A., Murillo-Cremaes, N., Hortelão, A. C., Patinño, T., Villalonga, R., Sancenón, F., Martínez-Máñer, R., Sánchez, S., (2019). Enzyme-powered gated mesoporous silica nanomotors for on-command intracellular payload delivery ACS Nano 13, (10), 12171-12183

The introduction of stimuli-responsive cargo release capabilities on self-propelled micro- and nanomotors holds enormous potential in a number of applications in the biomedical field. Herein, we report the preparation of mesoporous silica nanoparticles gated with pH-responsive supramolecular nanovalves and equipped with urease enzymes which act as chemical engines to power the nanomotors. The nanoparticles are loaded with different cargo molecules ([Ru(bpy)3]Cl2 (bpy = 2,2′-bipyridine) or doxorubicin), grafted with benzimidazole groups on the outer surface, and capped by the formation of inclusion complexes between benzimidazole and cyclodextrin-modified urease. The nanomotor exhibits enhanced Brownian motion in the presence of urea. Moreover, no cargo is released at neutral pH, even in the presence of the biofuel urea, due to the blockage of the pores by the bulky benzimidazole:cyclodextrin-urease caps. Cargo delivery is only triggered on-command at acidic pH due to the protonation of benzimidazole groups, the dethreading of the supramolecular nanovalves, and the subsequent uncapping of the nanoparticles. Studies with HeLa cells indicate that the presence of biofuel urea enhances nanoparticle internalization and both [Ru(bpy)3]Cl2 or doxorubicin intracellular release due to the acidity of lysosomal compartments. Gated enzyme-powered nanomotors shown here display some of the requirements for ideal drug delivery carriers such as the capacity to self-propel and the ability to “sense” the environment and deliver the payload on demand in response to predefined stimuli.

Keywords: Controlled release, Drug delivery, Enzymatic catalysis, Gatekeepers, Nanocarriers, Nanomotors, Stimuli-responsive nanomaterials


Palmisano, I., Danzi, M. C., Hutson, T. H., Zhou, L., McLachlan, E., Serger, E., Shkura, K., Srivastava, P. K., Hervera, A., Neill, N. O., Liu, T., Dhrif, H., Wang, Z., Kubat, M., Wuchty, S., Merkenschlager, M., Levi, L., Elliott, E., Bixby, J. L., Lemmon, V. P., Di Giovanni, S., (2019). Epigenomic signatures underpin the axonal regenerative ability of dorsal root ganglia sensory neurons Nature Neuroscience 22, (11), 1913-1924

Axonal injury results in regenerative success or failure, depending on whether the axon lies in the peripheral or the CNS, respectively. The present study addresses whether epigenetic signatures in dorsal root ganglia discriminate between regenerative and non-regenerative axonal injury. Chromatin immunoprecipitation for the histone 3 (H3) post-translational modifications H3K9ac, H3K27ac and H3K27me3; an assay for transposase-accessible chromatin; and RNA sequencing were performed in dorsal root ganglia after sciatic nerve or dorsal column axotomy. Distinct histone acetylation and chromatin accessibility signatures correlated with gene expression after peripheral, but not central, axonal injury. DNA-footprinting analyses revealed new transcriptional regulators associated with regenerative ability. Machine-learning algorithms inferred the direction of most of the gene expression changes. Neuronal conditional deletion of the chromatin remodeler CCCTC-binding factor impaired nerve regeneration, implicating chromatin organization in the regenerative competence. Altogether, the present study offers the first epigenomic map providing insight into the transcriptional response to injury and the differential regenerative ability of sensory neurons.

Keywords: Cell biology, Computational biology and bioinformatics, Molecular biology, Neuroscience


Minguela, J., Slawik, S., Mücklich, F., Ginebra, M. P., Llanes, L., Mas-Moruno, C., Roa, J. J., (2019). Evolution of microstructure and residual stresses in gradually ground/polished 3Y-TZP Journal of the European Ceramic Society In press

A comprehensive study of progressively ground/polished 3Y-TZP was performed with the aim of better understanding the mechanisms driving the microstructural modifications observed after such procedures, and identifying the processing parameters leading to optimal microstructures (i.e. ageing-protective and damage-free). Gradually ground/polished surfaces were produced, yielding four different topographies of increasing roughness (grades 1–4) and two different textures (unidirectionally, U, and multidirectionally, M). Phase transformation, microstructure and residual stresses were investigated by means of advanced characterization techniques. It was found that low-roughness mildly ground/polished specimens (i.e. 2-M/U) presented a nanometric layer with the ageing-related protective features generally associated with coarsely ground specimens. A lower limit for grain refinement in terms of surface abrasion was also found, in which partial recrystallization took place (i.e. 1-M/U). A mathematical relation was established between average surface roughness (Sa), monoclinic volume fraction (Vm) and surface compressive residual stresses, demonstrating that if the processing parameters are controlled, both Vm and residual stresses can be predicted by the measurement of Sa.

Keywords: Grinding, Microstructure, Phase transformation, Residual stresses, Zirconia


Hüttener, M., Prieto, A., Aznar, S., Bernabeu, M., Glaría, E., Valledor, A. F., Paytubi, S., Merino, S., Tomás, J., Juárez, A., (2019). Expression of a novel class of bacterial Ig-like proteins is required for IncHI plasmid conjugation PLoS Genetics 15, (9), e1008399

Antimicrobial resistance (AMR) is currently one of the most important challenges to the treatment of bacterial infections. A critical issue to combat AMR is to restrict its spread. In several instances, bacterial plasmids are involved in the global spread of AMR. Plasmids belonging to the incompatibility group (Inc)HI are widespread in Enterobacteriaceae and most of them express multiple antibiotic resistance determinants. They play a relevant role in the recent spread of colistin resistance. We present in this report novel findings regarding IncHI plasmid conjugation. Conjugative transfer in liquid medium of an IncHI plasmid requires expression of a plasmid-encoded, large-molecular-mass protein that contains an Ig-like domain. The protein, termed RSP, is encoded by a gene (ORF R0009) that maps in the Tra2 region of the IncHI1 R27 plasmid. The RSP protein is exported outside the cell by using the plasmid-encoded type IV secretion system that is also used for its transmission to new cells. Expression of the protein reduces cell motility and enables plasmid conjugation. Flagella are one of the cellular targets of the RSP protein. The RSP protein is required for a high rate of plasmid transfer in both flagellated and nonflagellated Salmonella cells. This effect suggests that RSP interacts with other cellular structures as well as with flagella. These unidentified interactions must facilitate mating pair formation and, hence, facilitate IncHI plasmid conjugation. Due to its location on the outer surfaces of the bacterial cell, targeting the RSP protein could be a means of controlling IncHI plasmid conjugation in natural environments or of combatting infections caused by AMR enterobacteria that harbor IncHI plasmids.


Park, D., Wershof, E., Boeing, S., Labernadie, A., Jenkins, R. P., George, S., Trepat, X., Bates, P. A., Sahai, E., (2019). Extracellular matrix anisotropy is determined by TFAP2C-dependent regulation of cell collisions Nature Materials Article in Press

The isotropic or anisotropic organization of biological extracellular matrices has important consequences for tissue function. We study emergent anisotropy using fibroblasts that generate varying degrees of matrix alignment from uniform starting conditions. This reveals that the early migratory paths of fibroblasts are correlated with subsequent matrix organization. Combined experimentation and adaptation of Vicsek modelling demonstrates that the reorientation of cells relative to each other following collision plays a role in generating matrix anisotropy. We term this behaviour ‘cell collision guidance’. The transcription factor TFAP2C regulates cell collision guidance in part by controlling the expression of RND3. RND3 localizes to cell–cell collision zones where it downregulates actomyosin activity. Cell collision guidance fails without this mechanism in place, leading to isotropic matrix generation. The cross-referencing of alignment and TFAP2C gene expression signatures against existing datasets enables the identification and validation of several classes of pharmacological agents that disrupt matrix anisotropy.

Keywords: Biomaterials – cells, Cell migration, Self-assembly, Tissues


Martinez, Dominique, Burgués, Javier, Marco, Santiago, (2019). Fast measurements with MOX sensors: A least-squares approach to blind deconvolution Sensors 19, (18), 4029

Metal oxide (MOX) sensors are widely used for chemical sensing due to their low cost, miniaturization, low power consumption and durability. Yet, getting instantaneous measurements of fluctuating gas concentration in turbulent plumes is not possible due to their slow response time. In this paper, we show that the slow response of MOX sensors can be compensated by deconvolution, provided that an invertible, parametrized, sensor model is available. We consider a nonlinear, first-order dynamic model that is mathematically tractable for MOX identification and deconvolution. By transforming the sensor signal in the log-domain, the system becomes linear in the parameters and these can be estimated by the least-squares techniques. Moreover, we use the MOX diversity in a sensor array to avoid training with a supervised signal. The information provided by two (or more) sensors, exposed to the same flow but responding with different dynamics, is exploited to recover the ground truth signal (gas input). This approach is known as blind deconvolution. We demonstrate its efficiency on MOX sensors recorded in turbulent plumes. The reconstructed signal is similar to the one obtained with a fast photo-ionization detector (PID). The technique is thus relevant to track a fast-changing gas concentration with MOX sensors, resulting in a compensated response time comparable to that of a PID.

Keywords: MOX sensors, Blind deconvolution, Blind identification, Least-squares, Turbulent plumes.


Faron, A., Pieper, C. C., Schmeel, F. C., Sprinkart, A. M., Kuetting, D. L. R., Fimmers, R., Trebicka, J., Schild, H. H., Meyer, C., Thomas, D., Luetkens, J. A., (2019). Fat-free muscle area measured by magnetic resonance imaging predicts overall survival of patients undergoing radioembolization of colorectal cancer liver metastases European Radiology 29, (9), 4709-4717

Objectives: To investigate the clinical potential of fat-free muscle area (FFMA) to predict outcome in patients with liver-predominant metastatic colorectal cancer (mCRC) undergoing radioembolization (RE) with 90Yttrium microspheres. Methods: Patients with mCRC who underwent RE in our center were included in this retrospective study. All patients received liver magnetic resonance imaging including standard T2-weighted images. The total erector spinae muscle area and the intramuscular adipose tissue area were measured at the level of the origin of the superior mesenteric artery and subtracted to calculate FFMA. Cutoff values for definition of low FFMA were 3644 mm2 in men and 2825 mm2 in women. The main outcome was overall survival (OS). For survival analysis, the Kaplan-Meier method and Cox regressions comparing various clinic-oncological parameters which potentially may affect OS were performed. Results: Seventy-seven patients (28 female, mean age 60 ± 11 years) were analyzed. Mean time between MRI and the following RE was 17 ± 31 days. Median OS after RE was 178 days. Patients with low FFMA had significantly shortened OS compared to patients with high FFMA (median OS: 128 vs. 273 days, p = 0.017). On multivariate Cox regression analysis, OS was best predicted by FFMA (hazard ratio (HR) 2.652; p < 0.001). Baseline bilirubin (HR 1.875; p = 0.030), pattern of tumor manifestation (HR 1.679; p = 0.001), and model of endstage liver disease (MELD) score (HR 1.164; p < 0.001) were also significantly associated with OS. Conclusions: FFMA was associated with OS in patients receiving RE for treatment of mCRC and might be a new prognostic biomarker for survival prognosis.

Keywords: Brachytherapy, Colorectal cancer, Magnetic resonance imaging, Sarcopenia


Marti-Muñoz, Joan, Xuriguera, Elena, Layton, John W., Planell, Josep A., Rankin, Stephen E., Engel, Elisabeth, Castaño, Oscar, (2019). Feasible and pure P2O5-CaO nanoglasses: An in-depth NMR study of synthesis for the modulation of the bioactive ion release Acta Biomaterialia 94, 574-584

The use of bioactive glasses (e.g. silicates, phosphates, borates) has demonstrated to be an effective therapy for the restoration of bone fractures, wound healing and vascularization. Their partial dissolution towards the surrounding tissue has shown to trigger positive bioactive responses, without the necessity of using growth factors or cell therapy, which reduces money-costs, side effects and increases their translation to the clinics. However, bioactive glasses often need from stabilizers (e.g. SiO44−, Ti4+, Co2+, etc.) that are not highly abundant in the body and which metabolization is not fully understood. In this study, we were focused on synthesizing pure calcium phosphate glasses without the presence of such stabilizers. We combined a mixture of ethylphosphate and calcium 2-methoxyethoxide to synthesize nanoparticles with different compositions and degradability. Synthesis was followed by an in-depth nuclear magnetic resonance characterization, complemented with other techniques that helped us to correlate the chemical structure of the glasses with their physiochemical properties and reaction mechanism. After synthesis, the organically modified xerogel (i.e. calcium monoethylphosphate) was treated at 200 or 350 °C and its solubility was maintained and controlled due to the elimination of organics, increase of phosphate-calcium interactions and phosphate polycondensation. To the best of our knowledge, we are reporting the first sol-gel synthesis of binary (P2O5-CaO) calcium phosphate glass nanoparticles in terms of continuous polycondensated phosphate chains structure without the addition of extra ions. The main goal is to straightforward the synthesis, to get a safer metabolization and to modulate the bioactive ion release. Additionally, we shed light on the chemical structure, reaction mechanism and properties of calcium phosphate glasses with high calcium contents, which nowadays are poorly understood. Statement of Significance The use of bioactive inorganic materials (i.e. bioactive ceramics, glass-ceramics and glasses) for biomedical applications is attractive due to their good integration with the host tissue without the necessity of adding exogenous cells or growth factors. In particular, degradable calcium phosphate glasses are completely resorbable, avoiding the retention in the body of the highly stable silica network of silicate glasses, and inducing a more controllable degradability than bioactive ceramics. However, most calcium phosphate glasses include the presence of stabilizers (e.g. Ti4+, Na+, Co2+), which metabolization is not fully understood and complicates their synthesis. The development of binary calcium phosphate glasses with controlled degradability reduces these limitations, offering a simple and completely metabolizable material with higher transfer to the clinics.

Keywords: Calcium phosphate glasses, Sol-gel process, NMR spectroscopy, Ion release, Biomaterials


Praktiknjo, M., Djayadi, N., Mohr, R., Schierwagen, R., Bischoff, J., Dold, L., Pohlmann, A., Schwarze-Zander, C., Wasmuth, J. C., Boesecke, C., Rockstroh, J. K., Trebicka, J., (2019). Fibroblast growth factor 21 is independently associated with severe hepatic steatosis in non-obese HIV-infected patients Liver International 39, (8), 1514-1520

Background: Severe hepatic steatosis shows a high prevalence and contributes to morbidity and mortality in human immunodeficiency virus (HIV) infected patients. Known risk factors include obesity, dyslipidaemia and features of metabolic syndrome. Fibroblast growth factor 21 (FGF-21) is involved with hepatic glucose and lipid metabolism. This study aimed to evaluate FGF-21 as a biomarker for severe hepatic steatosis in non-obese HIV-infected patients. Methods: This is a prospective, cross-sectional, monocentric study including HIV-infected out-patients. Hepatic steatosis was measured via controlled attenuation parameter (CAP) using FibroScan 502 touch (ECHOSENS, France). Severe hepatic steatosis was defined at CAP ≥ 253 dB/m. Peripheral blood samples were collected and plasma was analysed for FGF-21. Demographic and clinical characteristics were collected from patient's health records. Results: In total, 73 non-obese HIV-monoinfected patients were included in this study. Prevalence of severe hepatic steatosis was 41%. Patients with severe hepatic steatosis showed significantly higher levels of FGF-21. Univariate analysis revealed FGF-21, BMI, hyperlipidaemia, ALT levels and arterial hypertension as significant, while multivariate analysis showed only FGF-21, arterial hypertension and ALT levels as significant independent risk factors for severe hepatic steatosis. Conclusion: This study presents FGF-21 as an independent and stronger predictor of severe hepatic steatosis than blood lipids in HIV-infected patients. Moreover, arterial hypertension and ALT levels predict severe steatosis even in non-obese HIV-monoinfected patients. Furthermore, this study supports existing metabolic risk factors and expands them to non-obese HIV-infected patients.

Keywords: BMI, CAP, Dyslipidaemia, FGF-21, Fibroscan, HIV, Hyperlipidaemia, Liver, NAFLD, NASH, Steatosis


Garreta, Elena, Prado, Patricia, Tarantino, Carolina, Oria, Roger, Fanlo, Lucia, Martí, Elisa, Zalvidea, Dobryna, Trepat, Xavier, Roca-Cusachs, Pere, Gavaldà -Navarro, Aleix, Cozzuto, Luca, Campistol, Josep M., Izpisúa Belmonte, Juan Carlos, Hurtado del Pozo, Carmen, Montserrat, Nuria, (2019). Fine tuning the extracellular environment accelerates the derivation of kidney organoids from human pluripotent stem cells Nature Materials 18, 397-405

The generation of organoids is one of the biggest scientific advances in regenerative medicine. Here, by lengthening the time that human pluripotent stem cells (hPSCs) were exposed to a three-dimensional microenvironment, and by applying defined renal inductive signals, we generated kidney organoids that transcriptomically matched second-trimester human fetal kidneys. We validated these results using ex vivo and in vitro assays that model renal development. Furthermore, we developed a transplantation method that utilizes the chick chorioallantoic membrane. This approach created a soft in vivo microenvironment that promoted the growth and differentiation of implanted kidney organoids, as well as providing a vascular component. The stiffness of the in ovo chorioallantoic membrane microenvironment was recapitulated in vitro by fabricating compliant hydrogels. These biomaterials promoted the efficient generation of renal vesicles and nephron structures, demonstrating that a soft environment accelerates the differentiation of hPSC-derived kidney organoids.


Agnetta, L., Bermudez, M., Riefolo, F., Matera, C., Claro, E., Messerer, R., Littmann, T., Wolber, G., Holzgrabe, U., Decker, M., (2019). Fluorination of photoswitchable muscarinic agonists tunes receptor pharmacology and photochromic properties Journal of Medicinal Chemistry 62, (6), 3009-3020

Red-shifted azobenzene scaffolds have emerged as useful molecular photoswitches to expand potential applications of photopharmacological tool compounds. As one of them, tetra-ortho-fluoro azobenzene is well compatible for the design of visible-light-responsive systems, providing stable and bidirectional photoconversions and tissue-compatible characteristics. Using the unsubstituted azobenzene core and its tetra-ortho-fluorinated analogue, we have developed a set of uni- and bivalent photoswitchable toolbox derivatives of the highly potent muscarinic acetylcholine receptor agonist iperoxo. We investigated the impact of the substitution pattern on receptor activity and evaluated the different binding modes. Compounds 9b and 15b show excellent photochemical properties and biological activity as fluorination of the azobenzene core alters not only the photochromic behavior but also the pharmacological profile at the muscarinic M1 receptor. These findings demonstrate that incorporation of fluorinated azobenzenes not just may alter photophysical properties but can exhibit a considerably different biological profile that has to be carefully investigated.


Sánchez-Fibla, M., Forestier, S., Moulin-Frier, C., Puigbò, J. Y., Verschure, P., (2019). From motor to visually guided bimanual affordance learning Adaptive Behavior Article first published online

The mechanisms of how the brain orchestrates multi-limb joint action have yet to be elucidated and few computational sensorimotor (SM) learning approaches have dealt with the problem of acquiring bimanual affordances. We propose a series of bidirectional (forward/inverse) SM maps and its associated learning processes that generalize from uni- to bimanual interaction (and affordances) naturally, reinforcing the motor equivalence property. The SM maps range from a SM nature to a solely sensory one: full body control, delta SM control (through small action changes), delta sensory co-variation (how body-related perceptual cues covariate with object-related ones). We make several contributions on how these SM maps are learned: (1) Context and Behavior-Based Babbling: generalizing goal babbling to the interleaving of absolute and local goals including guidance of reflexive behaviors; (2) Event-Based Learning: learning steps are driven by visual, haptic events; and (3) Affordance Gradients: the vectorial field gradients in which an object can be manipulated. Our modeling of bimanual affordances is in line with current robotic research in forward visuomotor mappings and visual servoing, enforces the motor equivalence property, and is also consistent with neurophysiological findings like the multiplicative encoding scheme.

Keywords: Affordances, Bimanual affordances, Goal babbling, Interlimb coordination, Motor equivalence, Sensorimotor learning


Bloise, Ermelinda, Di Bello, Maria Pia, Mele, Giuseppe, Rizzello, Loris, (2019). A green method for the production of an efficient bioimaging nanotool Nanoscale Advances 1, (3), 1193-1199

The possibility of exploring basic biological phenomena requires the development of new and efficient bio-imaging tools. These should ideally combine the feasibility of production (potentially through the use of green chemistry) together with high targeting efficiency, low cytotoxicity, and optimal contrast characteristics. In this work, we developed nanovesicles based on cardanol, a natural and renewable byproduct of the cashew industry, and a fluorescent reporter was encapsulated in them through an environment-friendly synthesis method. In vitro investigations demonstrated that the cardanol nanovesicles are efficiently taken-up by both professional and non-professional phagocytic cells, which have been modeled in our approach by macrophages and HeLa cells, respectively. Co-localization studies show high affinity of the nanovesicles towards the cell plasma membrane. Moreover, metabolic assays confirmed that these nanostructures are biocompatible in a specific concentration range, and do not promote inflammation response in human macrophages. Stability studies carried out at different temperatures showed that the nanovesicles are stable at both 37 °C and 20 °C, while the formation of aggregates occurs when the nanodispersion is incubated at 4 °C. The results demonstrate the high potential of fluorescent cardanol nanovesicles as a green bioimaging tool, especially for investigating cell membrane dynamics.


Palacios, L. S., Katuri, J., Pagonabarraga, I., Sánchez, S., (2019). Guidance of active particles at liquid-liquid interfaces near surfaces Soft Matter 15, (32), 6581-6588

Artificial microswimmers have the potential for applications in many fields, ranging from targeted cargo delivery and mobile sensing to environmental remediation. In many of these applications, the artificial swimmers will operate in complex media necessarily involving liquid–liquid interfaces. Here, we experimentally study the motion of chemically powered phoretic active colloids close to liquid–liquid interfaces while swimming next to a solid substrate. In a system involving this complex geometry, we find that the active particles have an alignment interaction with both the neighbouring solid and liquid interfaces, allowing for a robust guiding mechanism along the liquid interface. We compare with minimal active Brownian simulations to show that these phoretically active particles stay along the interfaces for much longer times and lengths than expected for standard active Brownian particles. We also track the propulsion speeds of these particles and find a reduced speed close to the liquid–liquid interface. We report an interesting non-linear dependence of this reduction on the particle's bulk speed..


Vukomanovic, M., Torrents, E., (2019). High time resolution and high signal-to-noise monitoring of the bacterial growth kinetics in the presence of plasmonic nanoparticles Journal of Nanobiotechnology 17, (1), 21

Background: Emerging concepts for designing innovative drugs (i.e., novel generations of antimicrobials) frequently include nanostructures, new materials, and nanoparticles (NPs). Along with numerous advantages, NPs bring limitations, partly because they can limit the analytical techniques used for their biological and in vivo validation. From that standpoint, designing innovative drug delivery systems requires advancements in the methods used for their testing and investigations. Considering the well-known ability of resazurin-based methods for rapid detection of bacterial metabolisms with very high sensitivity, in this work we report a novel optimization for tracking bacterial growth kinetics in the presence of NPs with specific characteristics, such as specific optical properties. Results: Arginine-functionalized gold composite (HAp/Au/arginine) NPs, used as the NP model for validation of the method, possess plasmonic properties and are characterized by intensive absorption in the UV/vis region with a surface plasmon resonance maximum at 540 nm. Due to the specific optical properties, the NP absorption intensively interferes with the light absorption measured during the evaluation of bacterial growth (optical density; OD600). The results confirm substantial nonspecific interference by NPs in the signal detected during a regular turbidity study used for tracking bacterial growth. Instead, during application of a resazurin-based method (Presto Blue), when a combination of absorption and fluorescence detection is applied, a substantial increase in the signal-to-noise ratio is obtained that leads to the improvement of the accuracy of the measurements as verified in three bacterial strains tested with different growth rates (E. coli, P. aeruginosa, and S. aureus). Conclusions: Here, we described a novel procedure that enables the kinetics of bacterial growth in the presence of NPs to be followed with high time resolution, high sensitivity, and without sampling during the kinetic study. We showed the applicability of the Presto Blue method for the case of HAp/Au/arginine NPs, which can be extended to various types of metallic NPs with similar characteristics. The method is a very easy, economical, and reliable option for testing NPs designed as novel antimicrobials.

Keywords: Antimicrobial nanoparticles, Arginine-functionalized gold, Bacterial growth kinetics, Plasmonic nanoparticles, Presto Blue


Picón-Pagès, P., Bonet, J., García-García, J., Garcia-Buendia, J., Gutierrez, D., Valle, J., Gómez-Casuso, C. E. S., Sidelkivska, V., Alvarez, A., Perálvarez-Marín, A., Suades, A., Fernàndez-Busquets, X., Andreu, D., Vicente, R., Oliva, B., Muñoz, F. J., (2019). Human albumin impairs amyloid β-peptide fibrillation through its C-terminus: From docking modeling to protection against neurotoxicity in alzheimer's disease Computational and Structural Biotechnology Journal 17, 963-971

Alzheimer's disease (AD) is a neurodegenerative process characterized by the accumulation of extracellular deposits of amyloid β-peptide (Aβ), which induces neuronal death. Monomeric Aβ is not toxic but tends to aggregate into β-sheets that are neurotoxic. Therefore to prevent or delay AD onset and progression one of the main therapeutic approaches would be to impair Aβ assembly into oligomers and fibrils and to promote disaggregation of the preformed aggregate. Albumin is the most abundant protein in the cerebrospinal fluid and it was reported to bind Aβ impeding its aggregation. In a previous work we identified a 35-residue sequence of clusterin, a well-known protein that binds Aβ, that is highly similar to the C-terminus (CTerm) of albumin. In this work, the docking experiments show that the average binding free energy of the CTerm-Aβ1–42 simulations was significantly lower than that of the clusterin-Aβ1–42 binding, highlighting the possibility that the CTerm retains albumin's binding properties. To validate this observation, we performed in vitro structural analysis of soluble and aggregated 1 μM Aβ1–42 incubated with 5 μM CTerm, equimolar to the albumin concentration in the CSF. Reversed-phase chromatography and electron microscopy analysis demonstrated a reduction of Aβ1–42 aggregates when the CTerm was present. Furthermore, we treated a human neuroblastoma cell line with soluble and aggregated Aβ1–42 incubated with CTerm obtaining a significant protection against Aβ-induced neurotoxicity. These in silico and in vitro data suggest that the albumin CTerm is able to impair Aβ aggregation and to promote disassemble of Aβ aggregates protecting neurons.

Keywords: Albumin, Alzheimer's disease, Amyloid, Docking, β-Sheet


Vila, A., Torras, N., Castaño, Albert G., García-Díaz, María, Comelles, Jordi, Pérez-Berezo, T., Corregidor, C., Castaño, O., Engel, E., Fernández-Majada, Vanesa, Martínez, Elena, (2019). Hydrogel co-networks of gelatine methacrylate and poly(ethylene glycol) diacrylate sustain 3D functional in vitro models of intestinal mucosa Biofabrication Accepted Manuscript

Mounting evidence supports the importance of the intestinal epithelial barrier and its permeability both in physiological and pathological conditions. Conventional in vitro models to evaluate intestinal permeability rely on the formation of tightly packed epithelial monolayers grown on hard substrates. These two-dimensional (2D) models lack the cellular and mechanical components of the non-epithelial compartment of the intestinal barrier, the stroma, which are key contributors to the barrier permeability in vivo. Thus, advanced in vitro models approaching the in vivo tissue composition are fundamental to improve precision in drug absorption predictions, to provide a better understanding of the intestinal biology, and to faithfully represent related diseases. Here, we generate photo-crosslinked gelatine methacrylate (GelMA) - poly(ethylene glycol) diacrylate (PEGDA) hydrogel co-networks that provide the required mechanical and biochemical features to mimic both the epithelial and stromal compartments of the intestinal mucosa, i.e., they are soft, cell adhesive and cell-loading friendly, and suitable for long-term culturing. We show that fibroblasts can be embedded in the GelMA-PEGDA hydrogels while epithelial cells can grow on top to form a mature epithelial monolayer that exhibits barrier properties which closely mimic those of the intestinal barrier in vivo, as shown by the physiologically relevant transepithelial electrical resistance (TEER) and permeability values. The presence of fibroblasts in the artificial stroma compartment accelerates the formation of the epithelial monolayer and boosts the recovery of the epithelial integrity upon temporary barrier disruption, demonstrating that our system is capable of successfully reproducing the interaction between different cellular compartments. As such, our hydrogel co-networks offer a technologically simple yet sophisticated approach to produce functional three-dimensional (3D) in vitro models of epithelial barriers with epithelial and stromal cells arranged in a spatially relevant manner and near-physiological functionality.


Biosca, A., Dirscherl, L., Moles, E., Imperial, S., Fernàndez-Busquets, X., (2019). An immunopegliposome for targeted antimalarial combination therapy at the nanoscale Pharmaceutics 11, (7), 341

Combination therapies, where two drugs acting through different mechanisms are administered simultaneously, are one of the most efficient approaches currently used to treat malaria infections. However, the different pharmacokinetic profiles often exhibited by the combined drugs tend to decrease treatment efficacy as the compounds are usually eliminated from the circulation at different rates. To circumvent this obstacle, we have engineered an immunoliposomal nanovector encapsulating hydrophilic and lipophilic compounds in its lumen and lipid bilayer, respectively. The antimalarial domiphen bromide has been encapsulated in the liposome membrane with good efficiency, although its high IC50 of ca. 1 μM for living parasites complicates its use as immunoliposomal therapy due to erythrocyte agglutination. The conjugation of antibodies against glycophorin A targeted the nanocarriers to Plasmodium-infected red blood cells and to gametocytes, the sole malaria parasite stage responsible for the transmission from the human to the mosquito vector. The antimalarials pyronaridine and atovaquone, which block the development of gametocytes, have been co-encapsulated in glycophorin A-targeted immunoliposomes. The co-immunoliposomized drugs have activities significantly higher than their free forms when tested in in vitro Plasmodium falciparum cultures: Pyronaridine and atovaquone concentrations that, when encapsulated in immunoliposomes, resulted in a 50% inhibition of parasite growth had no effect on the viability of the pathogen when used as free drugs.

Keywords: Combination therapy, Immunoliposomes, Malaria, Nanomedicine, Nanotechnology, Plasmodium, Targeted drug delivery


Barba, A., Diez-Escudero, A., Espanol, M., Bonany, M., Sadowska, J. M., Guillem-Marti, J., Öhman-Mägi, C., Persson, C., Manzanares, M. C., Franch, J., Ginebra, M. P., (2019). Impact of biomimicry in the design of osteoinductive bone substitutes: Nanoscale matters ACS Applied Materials and Interfaces 11, (9), 8818-8830

Bone apatite consists of carbonated calcium-deficient hydroxyapatite (CDHA) nanocrystals. Biomimetic routes allow fabricating synthetic bone grafts that mimic biological apatite. In this work, we explored the role of two distinctive features of biomimetic apatites, namely, nanocrystal morphology (plate vs needle-like crystals) and carbonate content, on the bone regeneration potential of CDHA scaffolds in an in vivo canine model. Both ectopic bone formation and scaffold degradation were drastically affected by the nanocrystal morphology after intramuscular implantation. Fine-CDHA foams with needle-like nanocrystals, comparable in size to bone mineral, showed a markedly higher osteoinductive potential and a superior degradation than chemically identical coarse-CDHA foams with larger plate-shaped crystals. These findings correlated well with the superior bone-healing capacity showed by the fine-CDHA scaffolds when implanted intraosseously. Moreover, carbonate doping of CDHA, which resulted in small plate-shaped nanocrystals, accelerated both the intrinsic osteoinduction and the bone healing capacity, and significantly increased the cell-mediated resorption. These results suggest that tuning the chemical composition and the nanostructural features may allow the material to enter the physiological bone remodeling cycle, promoting a tight synchronization between scaffold degradation and bone formation.

Keywords: Biomimetic, Calcium phosphate, Carbonated apatite, Foaming, Nanostructure, Osteogenesis, Osteoinduction


Leguia, Marc G., Martínez, Cristina G. B., Malvestio, Irene, Campo, Adrià  Tauste, Rocamora, Rodrigo, Levnaji, Andrzejak, Ralph G., (2019). Inferring directed networks using a rank-based connectivity measure Physical Review E 99, (1), 012319

Inferring the topology of a network using the knowledge of the signals of each of the interacting units is key to understanding real-world systems. One way to address this problem is using data-driven methods like cross-correlation or mutual information. However, these measures lack the ability to distinguish the direction of coupling. Here, we use a rank-based nonlinear interdependence measure originally developed for pairs of signals. This measure not only allows one to measure the strength but also the direction of the coupling. Our results for a system of coupled Lorenz dynamics show that we are able to consistently infer the underlying network for a subrange of the coupling strength and link density. Furthermore, we report that the addition of dynamical noise can benefit the reconstruction. Finally, we show an application to multichannel electroencephalographic recordings from an epilepsy patient.


Montero, J., (2019). Ingestible macromolecule injectors Science Translational Medicine 11, (515), eaaz3720

A next-generation ingestible device uses microneedles for macromolecule administration in the small intestine to avoid subcutaneous injections.


Khurana, K., Guillem-Marti, J., Soldera, F., Mücklich, F., Canal, C., Ginebra, M. P., (2019). Injectable calcium phosphate foams for the delivery of Pitavastatin as osteogenic and angiogenic agent Journal of Biomedical Materials Research - Part B Applied Biomaterials Early View

Apatitic bone cements have been used as a clinical bone substitutes and drug delivery vehicles for therapeutic agents in orthopedic applications. This has led to their combination with different drugs with known ability to foster bone formation. Recent studies have evaluated Simvastatin for its role in enhanced bone regeneration, but its lipophilicity hampers incorporation and release to and from the bone graft. In this study, injectable calcium phosphate foams (i-CPF) based on α-tricalcium phosphate were loaded for the first time with Pitavastatin. The stability of the drug in different conditions relevant to this study, the effect of the drug on the i-CPFs properties, the release profile, and the in vitro biological performance with regard to mineralization and vascularization were investigated. Pitavastatin did not cause any changes in neither the micro nor the macro structure of the i-CPFs, which retained their biomimetic features. PITA-loaded i-CPFs showed a dose-dependent drug release, with early stage release kinetics clearly affected by the evolving microstructure due to the setting of cement. in vitro studies showed dose-dependent enhancement of mineralization and vascularization. Our findings contribute towards the design of controlled release with low drug dosing bone grafts: i-CPFs loaded with PITA as osteogenic and angiogenic agent.

Keywords: Controlled drug release, Endothelial progenitor cells, Mineralization, Rat mesenchymal stem cells, Vascularization


Kechagia, Jenny Z., Ivaska, Johanna, Roca-Cusachs, Pere, (2019). Integrins as biomechanical sensors of the microenvironment Nature Reviews Molecular Cell Biology 20, (8), 457-473

Integrins, and integrin-mediated adhesions, have long been recognized to provide the main molecular link attaching cells to the extracellular matrix (ECM) and to serve as bidirectional hubs transmitting signals between cells and their environment. Recent evidence has shown that their combined biochemical and mechanical properties also allow integrins to sense, respond to and interact with ECM of differing properties with exquisite specificity. Here, we review this work first by providing an overview of how integrin function is regulated from both a biochemical and a mechanical perspective, affecting integrin cell-surface availability, binding properties, activation or clustering. Then, we address how this biomechanical regulation allows integrins to respond to different ECM physicochemical properties and signals, such as rigidity, composition and spatial distribution. Finally, we discuss the importance of this sensing for major cell functions by taking cell migration and cancer as examples.

Keywords: Cell migration, Extracellular matrix, Integrins, Mechanotransduction, Single-molecule biophysics


Ferrer, I., García, M. A., Carmona, M., Andrés-Benito, P., Torrejón-Escribano, B., Garcia-Esparcia, P., Del Rio, J. A., (2019). Involvement of oligodendrocytes in tau seeding and spreading in tauopathies Frontiers in Aging Neuroscience 11, 112

Introduction: Human tau seeding and spreading occur following intracerebral inoculation into different gray matter regions of brain homogenates obtained from tauopathies in transgenic mice expressing wild or mutant tau, and in wild-type (WT) mice. However, little is known about tau propagation following inoculation in the white matter. Objectives: The present study is geared to learning about the patterns of tau seeding and cells involved following unilateral inoculation in the corpus callosum of homogenates from sporadic Alzheimer's disease (AD), primary age-related tauopathy (PART: neuronal 4Rtau and 3Rtau), pure aging-related tau astrogliopathy (ARTAG: astroglial 4Rtau with thorn-shaped astrocytes TSAs), globular glial tauopathy (GGT: 4Rtau with neuronal tau and specific tau inclusions in astrocytes and oligodendrocytes, GAIs and GOIs, respectively), progressive supranuclear palsy (PSP: 4Rtau with neuronal inclusions, tufted astrocytes and coiled bodies), Pick's disease (PiD: 3Rtau with characteristic Pick bodies in neurons and tau containing fibrillar astrocytes), and frontotemporal lobar degeneration linked to P301L mutation (FTLD-P301L: 4Rtau familial tauopathy). Methods: Adult WT mice were inoculated unilaterally in the lateral corpus callosum with sarkosyl-insoluble fractions or with sarkosyl-soluble fractions from the mentioned tauopathies; mice were killed from 4 to 7 months after inoculation. Brains were fixed in paraformaldehyde, embedded in paraffin and processed for immunohistochemistry. Results: Tau seeding occurred in the ipsilateral corpus callosum and was also detected in the contralateral corpus callosum. Phospho-tau deposits were found in oligodendrocytes similar to coiled bodies and in threads. Moreover, tau deposits co-localized with active (phosphorylated) tau kinases p38 and ERK 1/2, suggesting active tau phosphorylation of murine tau. TSAs, GAIs, GOIs, tufted astrocytes, and tau-containing fibrillar astrocytes were not seen in any case. Tau deposits were often associated with slight myelin disruption and the presence of small PLP1-immunoreactive globules and dots in the ipsilateral corpus callosum 6 months after inoculation of sarkosyl-insoluble fractions from every tauopathy. Conclusions: Seeding and spreading of human tau in the corpus callosum of WT mice occurs in oligodendrocytes, thereby supporting the idea of a role of oligodendrogliopathy in tau seeding and spreading in the white matter in tauopathies. Slight differences in the predominance of threads or oligodendroglial deposits suggest disease differences in the capacity of tau seeding and spreading among tauopathies.

Keywords: AD, ARTAG, GGT, PiD, Seeding and spreading, Tau, Tauopathies


Rao, T. N., Hansen, N., Hilfiker, J., Rai, S., Majewska, J. M., Lekovic, D., Gezer, D., Andina, N., Galli, S., Cassel, T., Geier, F., Delezie, J., Nienhold, R., Hao-Shen, H., Beisel, C., Di Palma, S., Dimeloe, S., Trebicka, J., Wolf, D., Gassmann, M., Fan, T. W. M., Lane, A. N., Handschin, C., Dirnhofer, S., Kröger, N., Hess, C., Radimerski, T., Koschmieder, S., Cokic, V. P., Skoda, R. C., (2019). JAK2-mutant hematopoietic cells display metabolic alterations that can be targeted to treat myeloproliferative neoplasms Blood 134, (21), 1832-1846

Increased energy requirement and metabolic reprogramming are hallmarks of cancer cells. We show that metabolic alterations in hematopoietic cells are fundamental to the pathogenesis of mutant JAK2–driven myeloproliferative neoplasms (MPNs). We found that expression of mutant JAK2 augmented and subverted metabolic activity of MPN cells, resulting in systemic metabolic changes in vivo, including hypoglycemia, adipose tissue atrophy, and early mortality. Hypoglycemia in MPN mouse models correlated with hyperactive erythropoiesis and was due to a combination of elevated glycolysis and increased oxidative phosphorylation. Modulating nutrient supply through high-fat diet improved survival, whereas high-glucose diet augmented the MPN phenotype. Transcriptomic and metabolomic analyses identified numerous metabolic nodes in JAK2-mutant hematopoietic stem and progenitor cells that were altered in comparison with wild-type controls. We studied the consequences of elevated levels of Pfkfb3, a key regulatory enzyme of glycolysis, and found that pharmacological inhibition of Pfkfb3 with the small molecule 3PO reversed hypoglycemia and reduced hematopoietic manifestations of MPNs. These effects were additive with the JAK1/2 inhibitor ruxolitinib in vivo and in vitro. Inhibition of glycolysis by 3PO altered the redox homeostasis, leading to accumulation of reactive oxygen species and augmented apoptosis rate. Our findings reveal the contribution of metabolic alterations to the pathogenesis of MPNs and suggest that metabolic dependencies of mutant cells represent vulnerabilities that can be targeted for treating MPNs.


Chen, Tianchi, Callan-Jones, Andrew, Fedorov, Eduard, Ravasio, Andrea, Brugués, Agustí, Ong, Hui Ting, Toyama, Yusuke, Low, Boon Chuan, Trepat, Xavier, Shemesh, Tom, Voituriez, Raphaël, Ladoux, Benoît, (2019). Large-scale curvature sensing by directional actin flow drives cellular migration mode switching Nature Physics 15, (4), 393-402

Cell migration over heterogeneous substrates during wound healing or morphogenetic processes leads to shape changes driven by different organizations of the actin cytoskeleton and by functional changes including lamellipodial protrusions and contractile actin cables. Cells distinguish between cell-sized positive and negative curvatures in their physical environment by forming protrusions at positive curvatures and actin cables at negative curvatures; however, the cellular mechanisms remain unclear. Here, we report that concave edges promote polarized actin structures with actin flow directed towards the cell edge, in contrast to well-documented retrograde flow at convex edges. Anterograde flow and contractility induce a tension anisotropy gradient. A polarized actin network is formed, accompanied by a local polymerization–depolymerization gradient, together with leading-edge contractile actin cables in the front. These cables extend onto non-adherent regions while still maintaining contact with the substrate through focal adhesions. The contraction and dynamic reorganization of this actin structure allows forward movements enabling cell migration over non-adherent regions on the substrate. These versatile functional structures may help cells sense and navigate their environment by adapting to external geometric and mechanical cues.

Keywords: Biopolymers in vivo, Cellular motility


Pollastri, S., Jorba, I., Hawkins, T. J., Llusià , J., Michelozzi, M., Navajas, D., Peñuelas, J., Hussey, P. J., Knight, M. R., Loreto, F., (2019). Leaves of isoprene-emitting tobacco plants maintain PSII stability at high temperatures New Phytologist 223, (3), 1307-1318

At high temperatures, isoprene-emitting plants display a higher photosynthetic rate and a lower nonphotochemical quenching (NPQ) compared with nonemitting plants. The mechanism of this phenomenon, which may be very important under current climate warming, is still elusive. NPQ was dissected into its components, and chlorophyll fluorescence lifetime imaging microscopy (FLIM) was used to analyse the dynamics of excited chlorophyll relaxation in isoprene-emitting and nonemitting plants. Thylakoid membrane stiffness was also measured using atomic force microscope (AFM) to identify a possible mode of action of isoprene in improving photochemical efficiency and photosynthetic stability. We show that, when compared with nonemitters, isoprene-emitting tobacco plants exposed at high temperatures display a reduced increase of the NPQ energy-dependent component (qE) and stable (1) chlorophyll fluorescence lifetime; (2) amplitude of the fluorescence decay components; and (3) thylakoid membrane stiffness. Our study shows for the first time that isoprene maintains PSII stability at high temperatures by preventing the modifications of the surrounding environment, namely providing a more steady and homogeneous distribution of the light-absorbing centres and a stable thylakoid membrane stiffness. Isoprene photoprotects leaves with a mechanism alternative to NPQ, enabling plants to maintain a high photosynthetic rate at rising temperatures.

Keywords: (High) temperature, Atomic force microscopy (AFM), Chlorophyll fluorescence (quenching and lifetime), Fluorescence lifetime imaging microscopy (FLIM), Isoprene, Nonphotochemical quenching (NPQ), Photosynthesis


Gouveia, Virgínia M., Rizzello, Loris, Nunes, Claudia, Poma, Alessandro, Ruiz-Perez, Lorena, Oliveira, António, Reis, Salette, Battaglia, Giuseppe, (2019). Macrophage targeting pH responsive polymersomes for glucocorticoid therapy Pharmaceutics 11, (11), 614

Glucocorticoid (GC) drugs are the cornerstone therapy used in the treatment of inflammatory diseases. Here, we report pH responsive poly(2-methacryloyloxyethyl phosphorylcholine)–poly(2-(diisopropylamino)ethyl methacrylate) (PMPC–PDPA) polymersomes as a suitable nanoscopic carrier to precisely and controllably deliver GCs within inflamed target cells. The in vitro cellular studies revealed that polymersomes ensure the stability, selectivity and bioavailability of the loaded drug within macrophages. At molecular level, we tested key inflammation-related markers, such as the nuclear factor-κB, tumour necrosis factor-α, interleukin-1β, and interleukin-6. With this, we demonstrated that pH responsive polymersomes are able to enhance the anti-inflammatory effect of loaded GC drug. Overall, we prove the potential of PMPC–PDPA polymersomes to efficiently promote the inflammation shutdown, while reducing the well-known therapeutic limitations in GC-based therapy.

Keywords: Inflammation, Macrophages, Glucocorticoid, Polymersomes


Casanellas, Ignasi, Lagunas, Anna, Vida, Yolanda, Pérez-Inestrosa, Ezequiel, Andrades, José A., Becerra, José, Samitier, Josep, (2019). Matrix nanopatterning regulates mesenchymal differentiation through focal adhesion size and distribution according to cell fate Biomimetics 4, (2), 43

Extracellular matrix remodeling plays a pivotal role during mesenchyme patterning into different lineages. Tension exerted from cell membrane receptors bound to extracellular matrix ligands is transmitted by the cytoskeleton to the cell nucleus inducing gene expression. Here, we used dendrimer-based arginine–glycine–aspartic acid (RGD) uneven nanopatterns, which allow the control of local surface adhesiveness at the nanoscale, to unveil the adhesive requirements of mesenchymal tenogenic and osteogenic commitments. Cell response was found to depend on the tension resulting from cell–substrate interactions, which affects nuclear morphology and is regulated by focal adhesion size and distribution.

Keywords: Arginine–glycine–aspartic acid (RGD), Nanopattern, Mesenchymal stem cells, Tenogenesis, Osteogenesis, Cell nuclei, Focal adhesions


Infante, Elvira, Stannard, Andrew, Board, Stephanie J., Rico-Lastres, Palma, Rostkova, Elena, Beedle, Amy E. M., Lezamiz, Ainhoa, Wang, Yong Jian, Gulaidi Breen, Samuel, Panagaki, Fani, Sundar Rajan, Vinoth, Shanahan, Catherine, Roca-Cusachs, Pere, Garcia-Manyes, Sergi, (2019). The mechanical stability of proteins regulates their translocation rate into the cell nucleus Nature Physics Epub ahead of print

A cell’s ability to react to mechanical stimuli is known to be affected by the transport of transcription factors, the proteins responsible for regulating transcription of DNA into RNA, across the membrane enveloping its nucleus. Yet the molecular mechanisms by which mechanical cues control this process remain unclear. Here we show that one such protein, myocardin-related transcription factor A (MRTFA), is imported into the nucleus at a rate that is inversely correlated with its nanomechanical stability, but independent of its thermodynamic stability. Attaching mechanically stable proteins to MRTFA results in reduced gene expression and the subsequent slowing down of cell migration. We conclude that the mechanical unfolding of proteins regulates their nuclear translocation rate, and highlight the role of the nuclear pore complex as a selective mechanosensor that is capable of detecting forces as low as 10 pN. The modulation of the mechanical stability of transcription factors may represent a general strategy for the control of gene expression.

Keywords: Biological physics, Biophysics, Chemistry, Nanoscience and technology


Zhu, Yunqing, Poma, Alessandro, Rizzello, Loris, Gouveia, Virginia, Ruiz Perez, Lorena, Battaglia, Guiseppe, Williams, Charlotte Katherine, (2019). Metabolic-active fully hydrolysable polymersomes Angewandte Chemie International Edition 58, (14), 4581-4586

The synthesis and aqueous self-assembly of a new class of amphiphilic aliphatic polyesters are presented. These AB block polyesters comprise polycaprolactone (hydrophobe) and an alternating polyester from succinic acid and an ether substituted epoxide (hydrophile). They self-assemble into biodegradable polymersomes capable of entering cells. Their degradation products are bioactive giving rise to differentiated cellular responses inducing stromal cell proliferation and macrophage apoptosis. Both effects emerge only when the copolymers enter cells as polymersomes and their magnitudes are size dependent.


Martí Coma-Cros, E., Lancelot, A., San Anselmo, M., Neves Borgheti-Cardoso, L., Valle-Delgado, J. J., Serrano, J. L., Fernàndez-Busquets, X., Sierra, T., (2019). Micelle carriers based on dendritic macromolecules containing bis-MPA and glycine for antimalarial drug delivery Biomaterials Science 7, (4), 1661-1674

Biomaterials for antimalarial drug transport still need to be investigated in order to attain nanocarriers that can tackle essential issues related to malaria treatment, e.g. complying with size requirements and targeting specificity for their entry into Plasmodium-infected red blood cells (pRBCs), and limiting premature drug elimination or drug resistance evolution. Two types of dendritic macromolecule that can form vehicles suitable for antimalarial drug transport are herein explored. A new hybrid dendritic-linear-dendritic block copolymer based on Pluronic® F127 and amino terminated 2,2′-bis(glycyloxymethyl)propionic acid dendrons with a poly(ester amide) skeleton (HDLDBC-bGMPA) and an amino terminated dendronized hyperbranched polymer with a polyester skeleton derived from 2,2′-bis(hydroxymethyl)propionic acid (DHP-bMPA) have provided self-assembled and unimolecular micelles. Both types of micelle carrier are biocompatible and exhibit appropriate sizes to enter into pRBCs. Targeting studies have revealed different behaviors for each nanocarrier that may open new perspectives for antimalarial therapeutic approaches. Whereas DHP-bMPA exhibits a clear targeting specificity for pRBCs, HDLDBC-bGMPA is incorporated by all erythrocytes. It has also been observed that DHP-bMPA and HDLDBC-bGMPA incorporate into human umbilical vein endothelial cells with different subcellular localization, i.e. cytosolic and nuclear, respectively. Drug loading capacity and encapsulation efficiencies for the antimalarial compounds chloroquine, primaquine and quinacrine ranging from 30% to 60% have been determined for both carriers. The resulting drug-loaded nanocarriers have been tested for their capacity to inhibit Plasmodium growth in in vitro and in vivo assays.


Hernández-Albors, Alejandro, Castaño, Albert G., Fernández-Garibay, Xiomara, Ortega, María Alejandra, Balaguer, Jordina, Ramón-Azcón, Javier, (2019). Microphysiological sensing platform for an in-situ detection of tissue-secreted cytokines Biosensors and Bioelectronics: X 2, 100025

Understanding the protein-secretion dynamics from single, specific tissues is critical toward the advancement of disease detection and treatments. However, such secretion dynamics remain difficult to measure in vivo due to the uncontrolled contributions from other tissue populations. Here, we describe an integrated platform designed for the reliable, near real-time measurements of cytokines secreted from an in vitro single-tissue model. In our setup, we grow 3D biomimetic tissues to discretize cytokine source, and we separate them from a magnetic microbead-based biosensing system using a Transwell insert. This design integrates physiochemically controlled biological activity, high-sensitivity protein detection (LOD < 20 pg mL−1), and rapid protein diffusion to enable non-invasive, near real-time measurements. To showcase the specificity and sensitivity of the system, we use our setup to probe the inflammatory process related to the protein Interleukine 6 (IL-6) and to the Tumor Necrosis Factor (TNF-α). We show that our setup can monitor the time-dependence profile of IL-6 and TNF-α secretion that results from the electrical and chemical stimulation of 3D skeletal muscle tissues. We demonstrate a novel and affordable methodology for discretizing the secretion kinetics of specific tissues for advancing metabolic-disorder studies and drug-screening applications.

Keywords: Microphysiological tissues, Tissue engineering, Electrochemical, biosensors, Magnetic particles, Skeletal muscle, Electric stimulation


Montero, J., (2019). Modeling endometrial disease using organoids Science Translational Medicine 11, (507), eaaz0304

Organoids generated from patient-derived endometrial tissue model the pathophysiology of endometrial disease and can be used for drug screening.


Moles, E., Kavallaris, M., Fernàndez-Busquets, X., (2019). Modeling the distribution of diprotic basic drugs in liposomal systems: Perspectives on malaria nanotherapy Frontiers in Pharmacology 10, 1064

Understanding how polyprotic compounds distribute within liposome (LP) suspensions is of major importance to design effective drug delivery strategies. Advances in this research field led to the definition of LP-based active drug encapsulation methods driven by transmembrane pH gradients with evidenced efficacy in the management of cancer and infectious diseases. An accurate modeling of membrane-solution drug partitioning is also fundamental when designing drug delivery systems for poorly endocytic cells, such as red blood cells (RBCs), in which the delivered payloads rely mostly on the passive diffusion of drug molecules across the cell membrane. Several experimental models have been proposed so far to predict the partitioning of polyprotic basic/acid drugs in artificial membranes. Nevertheless, the definition of a model in which the membrane-solution partitioning of each individual drug microspecies is studied relative to each other is still a topic of ongoing research. We present here a novel experimental approach based on mathematical modeling of drug encapsulation efficiency (EE) data in liposomal systems by which microspecies-specific partition coefficients are reported as a function of pH and phospholipid compositions replicating the RBC membrane in a simple and highly translatable manner. This approach has been applied to the study of several diprotic basic antimalarials of major clinical importance (quinine, primaquine, tafenoquine, quinacrine, and chloroquine) describing their respective microspecies distribution in phosphatidylcholine-LP suspensions. Estimated EE data according to the model described here closely fitted experimental values with no significant differences obtained in 75% of all pH/lipid composition-dependent conditions assayed. Additional applications studied include modeling drug EE in LPs in response to transmembrane pH gradients and lipid bilayer asymmetric charge, conditions of potential interest reflected in our previously reported RBC-targeted antimalarial nanotherapeutics.

Keywords: Distribution coefficient, Liposomal systems, Malaria therapy, Nanomedicine, Partition coefficient, PH-controlled drug encapsulation, Polyprotic drug, Targeted drug delivery


Torres-Sanchez, A., Millan, D., Arroyo, M., (2019). Modelling fluid deformable surfaces with an emphasis on biological interfaces Journal of Fluid Mechanics 872, 218-271

Fluid deformable surfaces are ubiquitous in cell and tissue biology, including lipid bilayers, the actomyosin cortex or epithelial cell sheets. These interfaces exhibit a complex interplay between elasticity, low Reynolds number interfacial hydrodynamics, chemistry and geometry, and govern important biological processes such as cellular traffic, division, migration or tissue morphogenesis. To address the modelling challenges posed by this class of problems, in which interfacial phenomena tightly interact with the shape and dynamics of the surface, we develop a general continuum mechanics and computational framework for fluid deformable surfaces. The dual solid–fluid nature of fluid deformable surfaces challenges classical Lagrangian or Eulerian descriptions of deforming bodies. Here, we extend the notion of arbitrarily Lagrangian–Eulerian (ALE) formulations, well-established for bulk media, to deforming surfaces. To systematically develop models for fluid deformable surfaces, which consistently treat all couplings between fields and geometry, we follow a nonlinear Onsager formalism according to which the dynamics minimizes a Rayleighian functional where dissipation, power input and energy release rate compete. Finally, we propose new computational methods, which build on Onsager’s formalism and our ALE formulation, to deal with the resulting stiff system of higher-order partial differential equations. We apply our theoretical and computational methodology to classical models for lipid bilayers and the cell cortex. The methods developed here allow us to formulate/simulate these models in their full three-dimensional generality, accounting for finite curvatures and finite shape changes.

Keywords: Capsule/cell dynamics, Computational methods, Membranes


Santos-Pata, Diogo, Zucca, Riccardo, López-Carral, Héctor, Verschure, P., (2019). Modulating grid cell scale and intrinsic frequencies via slow high-threshold conductances: A simplified model Neural Networks 119, 66-73

Grid cells in the medial entorhinal cortex (MEC) have known spatial periodic firing fields which provide a metric for the representation of self-location and path planning. The hexagonal tessellation pattern of grid cells scales up progressively along the MEC’s layer II dorsal-to-ventral axis. This scaling gradient has been hypothesized to originate either from inter-population synaptic dynamics as postulated by attractor networks, or from projected theta frequency waves to different axis levels, as in oscillatory models. Alternatively, cellular dynamics and specifically slow high-threshold conductances have been proposed to have an impact on the grid cell scale. To test the hypothesis that intrinsic hyperpolarization-activated cation currents account for both the scaled gradient and the oscillatory frequencies observed along the dorsal-to-ventral axis, we have modeled and analyzed data from a population of grid cells simulated with spiking neurons interacting through low-dimensional attractor dynamics. We observed that the intrinsic neuronal membrane properties of simulated cells were sufficient to induce an increase in grid scale and potentiate differences in the membrane potential oscillatory frequency. Overall, our results suggest that the after-spike dynamics of cation currents may play a major role in determining the grid cells’ scale and that oscillatory frequencies are a consequence of intrinsic cellular properties that are specific to different levels of the dorsal-to-ventral axis in the MEC layer II.

Keywords: Grid cells, Entorhinal, Hyperpolarization, Navigation, Space


Herreros, Ivan, Miquel, Laia, Blithikioti, Chrysanthi, Nuño, Laura, Rubio Ballester, Belen, Grechuta, Klaudia, Gual, Antoni, Balcells-Oliveró, Mercè, Verschure, P., (2019). Motor adaptation impairment in chronic cannabis users assessed by a visuomotor rotation task Journal of Clinical Medicine 8, (7), 1049

Background—The cerebellum has been recently suggested as an important player in the addiction brain circuit. Cannabis is one of the most used drugs worldwide, and its long-term effects on the central nervous system are not fully understood. No valid clinical evaluations of cannabis impact on the brain are available today. The cerebellum is expected to be one of the brain structures that are highly affected by prolonged exposure to cannabis, due to its high density in endocannabinoid receptors. We aim to use a motor adaptation paradigm to indirectly assess cerebellar function in chronic cannabis users (CCUs). Methods—We used a visuomotor rotation (VMR) task that probes a putatively-cerebellar implicit motor adaptation process together with the learning and execution of an explicit aiming rule. We conducted a case-control study, recruiting 18 CCUs and 18 age-matched healthy controls. Our main measure was the angular aiming error. Results—Our results show that CCUs have impaired implicit motor adaptation, as they showed a smaller rate of adaptation compared with healthy controls (drift rate: 19.3 +/− 6.8° vs. 27.4 +/− 11.6°; t(26) = −2.1, p = 0.048, Cohen’s d = −0.8, 95% CI = (−1.7, −0.15)). Conclusions—We suggest that a visuomotor rotation task might be the first step towards developing a useful tool for the detection of alterations in implicit learning among cannabis users.

Keywords: Cerebellum, Cannabis, Implicit motor learning, Motor adaptation, Visuomotor rotation


Sample, Matthew, Boulicault, Marion, Allen, Caley, Bashir, Rashid, Hyun, Insoo, Levis, Megan, Lowenthal, Caroline, Mertz, David, Montserrat, Nuria, Palmer, Megan J., Saha, Krishanu, Zartman, Jeremiah, (2019). Multi-cellular engineered living systems: building a community around responsible research on emergence Biofabrication 11, (4), 043001

Ranging from miniaturized biological robots to organoids, multi-cellular engineered living systems (M-CELS) pose complex ethical and societal challenges. Some of these challenges, such as how to best distribute risks and benefits, are likely to arise in the development of any new technology. Other challenges arise specifically because of the particular characteristics of M-CELS. For example, as an engineered living system becomes increasingly complex, it may provoke societal debate about its moral considerability, perhaps necessitating protection from harm or recognition of positive moral and legal rights, particularly if derived from cells of human origin. The use of emergence-based principles in M-CELS development may also create unique challenges, making the technology difficult to fully control or predict in the laboratory as well as in applied medical or environmental settings. In response to these challenges, we argue that the M-CELS community has an obligation to systematically address the ethical and societal aspects of research and to seek input from and accountability to a broad range of stakeholders and publics. As a newly developing field, M-CELS has a significant opportunity to integrate ethically responsible norms and standards into its research and development practices from the start. With the aim of seizing this opportunity, we identify two general kinds of salient ethical issues arising from M-CELS research, and then present a set of commitments to and strategies for addressing these issues. If adopted, these commitments and strategies would help define M-CELS as not only an innovative field, but also as a model for responsible research and engineering.

Keywords: Ethics, Society, Governance, Emergence, Moral considerability, Responsible innovation


Bolognesi, Benedetta, Faure, Andre J., Seuma, Mireia, Schmiedel, Jörrn M., Tartaglia, Gian Gaetano, Lehner, Ben, (2019). The mutational landscape of a prion-like domain Nature Communications 10, (1), 4162

Insoluble protein aggregates are the hallmarks of many neurodegenerative diseases. For example, aggregates of TDP-43 occur in nearly all cases of amyotrophic lateral sclerosis (ALS). However, whether aggregates cause cellular toxicity is still not clear, even in simpler cellular systems. We reasoned that deep mutagenesis might be a powerful approach to disentangle the relationship between aggregation and toxicity. We generated >50,000 mutations in the prion-like domain (PRD) of TDP-43 and quantified their toxicity in yeast cells. Surprisingly, mutations that increase hydrophobicity and aggregation strongly decrease toxicity. In contrast, toxic variants promote the formation of dynamic liquid-like condensates. Mutations have their strongest effects in a hotspot that genetic interactions reveal to be structured in vivo, illustrating how mutagenesis can probe the in vivo structures of unstructured proteins. Our results show that aggregation of TDP-43 is not harmful but protects cells, most likely by titrating the protein away from a toxic liquid-like phase.

Keywords: Computational biology and bioinformatics, Genomics, Mechanisms of disease, Neurodegeneration, Systems biology


Jorba, I., Beltrán, G., Falcones, B., Suki, B., Farré, R., García-Aznar, J. M., Navajas, D., (2019). Nonlinear elasticity of the lung extracellular microenvironment is regulated by macroscale tissue strain Acta Biomaterialia 92, 265-276

The extracellular matrix (ECM) of the lung provides physical support and key mechanical signals to pulmonary cells. Although lung ECM is continuously subjected to different stretch levels, detailed mechanics of the ECM at the scale of the cell is poorly understood. Here, we developed a new polydimethylsiloxane (PDMS) chip to probe nonlinear mechanics of tissue samples with atomic force microscopy (AFM). Using this chip, we performed AFM measurements in decellularized rat lung slices at controlled stretch levels. The AFM revealed highly nonlinear ECM elasticity with the microscale stiffness increasing with tissue strain. To correlate micro- and macroscale ECM mechanics, we also assessed macromechanics of decellularized rat lung strips under uniaxial tensile testing. The lung strips exhibited exponential macromechanical behavior but with stiffness values one order of magnitude lower than at the microscale. To interpret the relationship between micro- and macromechanical properties, we carried out a finite element (FE) analysis which revealed that the stiffness of the alveolar cell microenvironment is regulated by the global strain of the lung scaffold. The FE modeling also indicates that the scale dependence of stiffness is mainly due to the porous architecture of the lung parenchyma. We conclude that changes in tissue strain during breathing result in marked changes in the ECM stiffness sensed by alveolar cells providing tissue-specific mechanical signals to the cells. Statement of Significance: The micromechanical properties of the extracellular matrix (ECM) are a major determinant of cell behavior. The ECM is exposed to mechanical stretching in the lung and other organs during physiological function. Therefore, a thorough knowledge of the nonlinear micromechanical properties of the ECM at the length scale that cells probe is required to advance our understanding of cell-matrix interplay. We designed a novel PDMS chip to perform atomic force microscopy measurements of ECM micromechanics on decellularized rat lung slices at different macroscopic strain levels. For the first time, our results reveal that the microscale stiffness of lung ECM markedly increases with macroscopic tissue strain. Therefore, changes in tissue strain during breathing result in variations in ECM stiffness providing tissue-specific mechanical signals to lung cells.

Keywords: AFM, ECM micromechanics, Multiscale lung mechanics, Tensile testing


Farré, R., Trias, G., Solana, G., Ginovart, G., Gozal, D., Navajas, D., (2019). Novel approach for providing pediatric continuous positive airway pressure devices in low-income, underresourced regions American Journal of Respiratory and Critical Care Medicine 199, (1), 118-120

Blanco-Cabra, N., Vega-Granados, K., Moya-Andérico, L., Vukomanovic, M., Parra, A., Álvarez De Cienfuegos, L., Torrents, E., (2019). Novel oleanolic and maslinic acid derivatives as a promising treatment against Bacterial biofilm in nosocomial infections: An in vitro and in vivo study ACS Infectious Diseases 5, (9), 1581-1589

Oleanolic acid (OA) and maslinic acid (MA) are pentacyclic triterpenic compounds that abound in industrial olive oil waste. These compounds have renowned antimicrobial properties and lack cytotoxicity in eukaryotic cells as well as resistance mechanisms in bacteria. Despite these advantages, their antimicrobial activity has only been tested in vitro, and derivatives improving this activity have not been reported. In this work, a set of 14 OA and MA C-28 amide derivatives have been synthesized. Two of these derivatives, MA-HDA and OA-HDA, increase the in vitro antimicrobial activity of the parent compounds while reducing their toxicity in most of the Gram-positive bacteria tested, including a methicillin-resistant Staphylococcus aureus-MRSA. MA-HDA also shows an enhanced in vivo efficacy in a Galleria mellonella invertebrate animal model of infection. A preliminary attempt to elucidate their mechanism of action revealed that these compounds are able to penetrate and damage the bacterial cell membrane. More significantly, their capacity to reduce antibiofilm formation in catheters has also been demonstrated in two sets of conditions: a static and a more challenged continuous-flow S. aureus biofilm.

Keywords: Antibiofilm, Galleria mellonella, In vitro and in vivo antimicrobials, Maslinic and oleanolic acids, Natural products, Staphylococcus aureus


Riefolo, F., Matera, C., Garrido-Charles, A., Gomila, A., Sortino, R., Agnetta, L., Claro, E., Masgrau, R., Holzgrabe, U., Batlle, M., Decker, M., Guasch, E., Gorostiza, P., (2019). Optical control of cardiac function with a photoswitchable muscarinic agonist Journal of the American Chemical Society 141, (18), 7628-7636

Light-triggered reversible modulation of physiological functions offers the promise of enabling on-demand spatiotemporally controlled therapeutic interventions. Optogenetics has been successfully implemented in the heart, but significant barriers to its use in the clinic remain, such as the need for genetic transfection. Herein, we present a method to modulate cardiac function with light through a photoswitchable compound and without genetic manipulation. The molecule, named PAI, was designed by introduction of a photoswitch into the molecular structure of an M2 mAChR agonist. In vitro assays revealed that PAI enables light-dependent activation of M2 mAChRs. To validate the method, we show that PAI photoisomers display different cardiac effects in a mammalian animal model, and demonstrate reversible, real-time photocontrol of cardiac function in translucent wildtype tadpoles. PAI can also effectively activate M2 receptors using two-photon excitation with near-infrared light, which overcomes the scattering and low penetration of short-wave-length illumination, and offers new opportunities for intravital imaging and control of cardiac function.


Cendra, Maria del Mar, Blanco-Cabra, Núria, Pedraz, Lucas, Torrents, Eduard, (2019). Optimal environmental and culture conditions allow the in vitro coexistence of Pseudomonas aeruginosa and Staphylococcus aureus in stable biofilms Scientific Reports 9, (1), 16284

The coexistence between species that occurs in some infections remains hard to achieve in vitro since bacterial fitness differences eventually lead to a single organism dominating the mixed culture. Pseudomonas aeruginosa and Staphylococcus aureus are major pathogens found growing together in biofilms in disease-affected lungs or wounds. Herein, we tested and analyzed different culture media, additives and environmental conditions to support P. aeruginosa and S. aureus coexistence in vitro. We have unraveled the potential of DMEM to support the growth of these two organisms in mature cocultured biofilms (three days old) in an environment that dampens the pH rise. Our conditions use equal initial inoculation ratios of both strains and allow the stable formation of separate S. aureus microcolonies that grow embedded in a P. aeruginosa biofilm, as well as S. aureus biofilm overgrowth when bovine serum albumin is added to the system. Remarkably, we also found that S. aureus survival is strictly dependent on a well-characterized phenomenon of oxygen stratification present in the coculture biofilm. An analysis of differential tolerance to gentamicin and ciprofloxacin treatment, depending on whether P. aeruginosa and S. aureus were growing in mono- or coculture biofilms, was used to validate our in vitro coculture conditions.

Keywords: Applied microbiology, Biofilms


Tozzi, C., Walani, N., Arroyo, M., (2019). Out-of-equilibrium mechanochemistry and self-organization of fluid membranes interacting with curved proteins New Journal of Physics 21, (9), 093004

The function of biological membranes is controlled by the interaction of the fluid lipid bilayer with various proteins, some of which induce or react to curvature. These proteins can preferentially bind or diffuse towards curved regions of the membrane, induce or stabilize membrane curvature and sequester membrane area into protein-rich curved domains. The resulting tight interplay between mechanics and chemistry is thought to control organelle morphogenesis and dynamics, including traffic, membrane mechanotransduction, or membrane area regulation and tension buffering. Despite all these processes are fundamentally dynamical, previous work has largely focused on equilibrium and a self-consistent theoretical treatment of the dynamics of curvature sensing and generation has been lacking. Here, we develop a general theoretical and computational framework based on a nonlinear Onsager's formalism of irreversible thermodynamics for the dynamics of curved proteins and membranes. We develop variants of the model, one of which accounts for membrane curving by asymmetric crowding of bulky off-membrane protein domains. As illustrated by a selection of test cases, the resulting governing equations and numerical simulations provide a foundation to understand the dynamics of curvature sensing, curvature generation, and more generally membrane curvature mechano-chemistry.

Keywords: Curvature generation, Curvature sensing, Lipid bilayers, Membrane proteins


Montero, J., (2019). P21: One protein to rule cell fate Science Translational Medicine 11, (499), eaay3568

Early p21 expression controls cells’ proliferation/senescence fate after chemotherapy.


Hervera, Arnau, Santos, Celio X., De Virgiliis, Francesco, Shah, Ajay M., Di Giovanni, Simone, (2019). Paracrine mechanisms of redox signalling for postmitotic cell and tissue regeneration Trends in Cell Biology 29, (6), 514-530

Adult postmitotic mammalian cells, including neurons and cardiomyocytes, have a limited capacity to regenerate after injury. Therefore, an understanding of the molecular mechanisms underlying their regenerative ability is critical to advance tissue repair therapies. Recent studies highlight how redox signalling via paracrine cell-to-cell communication may act as a central mechanism coupling tissue injury with regeneration. Post-injury redox paracrine signalling can act by diffusion to nearby cells, through mitochondria or within extracellular vesicles, affecting specific intracellular targets such as kinases, phosphatases, and transcription factors, which in turn trigger a regenerative response. Here, we review redox paracrine signalling mechanisms in postmitotic tissue regeneration and discuss current challenges and future directions.


Queck, A., Thomas, D., Jansen, C., Schreiber, Y., Rüschenbaum, S., Praktiknjo, M., Schwarzkopf, K. M., Mücke, M. M., Schierwagen, R., Uschner, F. E., Meyer, C., Clària, J., Zeuzem, S., Geisslinger, G., Trebicka, J., Lange, C. M., (2019). Pathophysiological role of prostanoids in coagulation of the portal venous system in liver cirrhosis PLoS ONE 14, (10), e0222840

Background: Prostanoids are important regulators of platelet aggregation and thrombotic arterial diseases. Their involvement in the development of portal vein thrombosis, frequent in decompensated liver cirrhosis, is still not investigated. Methods: Therefore, we used pro-thrombotic venous milieu generation by bare metal stent transjugular intrahepatic portosystemic shunt insertion, to study the role of prostanoids in decompensated liver cirrhosis. Here, 89 patients receiving transjugular intrahepatic portosystemic shunt insertion were included in the study, and baseline levels of thromboxane B2, prostaglandin D2 and prostaglandin E2 were measured in the portal and the hepatic vein. Results: While the hepatic vein contained higher levels of thromboxane B2 than the portal vein, levels of prostaglandin E2 and D2 were higher in the portal vein (all P<0.0001). Baseline concentrations of thromboxane B2 in the portal vein were independently associated with an increase of portal hepatic venous pressure gradient during short term follow-up, as an indirect sign of thrombogenic potential (multivariable P = 0.004). Moreover, severity of liver disease was inversely correlated with portal as well as hepatic vein levels of prostaglandin D2 and E2 (all P<0.0001). Conclusions: Elevated portal venous thromboxane B2 concentrations are possibly associated with the extent of thrombogenic potential in patients with decompensated liver cirrhosis.


Lozano-García, M., Estrada, L., Jané, R., (2019). Performance evaluation of fixed sample entropy in myographic signals for inspiratory muscle activity estimation Entropy 21, (2), 183

Fixed sample entropy (fSampEn) has been successfully applied to myographic signals for inspiratory muscle activity estimation, attenuating interference from cardiac activity. However, several values have been suggested for fSampEn parameters depending on the application, and there is no consensus standard for optimum values. This study aimed to perform a thorough evaluation of the performance of the most relevant fSampEn parameters in myographic respiratory signals, and to propose, for the first time, a set of optimal general fSampEn parameters for a proper estimation of inspiratory muscle activity. Different combinations of fSampEn parameters were used to calculate fSampEn in both non-invasive and the gold standard invasive myographic respiratory signals. All signals were recorded in a heterogeneous population of healthy subjects and chronic obstructive pulmonary disease patients during loaded breathing, thus allowing the performance of fSampEn to be evaluated for a variety of inspiratory muscle activation levels. The performance of fSampEn was assessed by means of the cross-covariance of fSampEn time-series and both mouth and transdiaphragmatic pressures generated by inspiratory muscles. A set of optimal general fSampEn parameters was proposed, allowing fSampEn of different subjects to be compared and contributing to improving the assessment of inspiratory muscle activity in health and disease.

Keywords: Electromyography, Fixed sample entropy, Mechanomyography, Non-invasive physiological measurements, Oesophageal electromyography, Respiratory muscle


Maleeva, Galyna, Wutz, Daniel, Rustler, Karin, Nin-Hill, Alba, Rovira, Carme, Petukhova, Elena, Bautista-Barrufet, Antoni, Gomila-Juaneda, Alexandre, Scholze, Petra, Peiretti, Franck, Alfonso-Prieto, Mercedes, König, Burkhard, Gorostiza, Pau, Bregestovski, Piotr, (2019). A photoswitchable GABA receptor channel blocker British Journal of Pharmacology British journal of pharmacology , 176, (15), 2661-2677

BACKGROUND AND PURPOSE: Anion-selective Cys-loop receptors (GABA and glycine receptors) provide the main inhibitory drive in the CNS. Both types of receptor operate via chloride-selective ion channels, though with different kinetics, pharmacological profiles, and localization. Disequilibrium in their function leads to a variety of disorders, which are often treated with allosteric modulators. The few available GABA and glycine receptor channel blockers effectively suppress inhibitory currents in neurons, but their systemic administration is highly toxic. With the aim of developing an efficient light-controllable modulator of GABA receptors, we constructed azobenzene-nitrazepam (Azo-NZ1), which is composed of a nitrazepam moiety merged to an azobenzene photoisomerizable group. EXPERIMENTAL APPROACH: The experiments were carried out on cultured cells expressing Cys-loop receptors of known subunit composition and in brain slices using patch-clamp. Site-directed mutagenesis and molecular modelling approaches were applied to evaluate the mechanism of action of Azo-NZ1. KEY RESULTS: At visible light, being in trans‐configuration, Azo-NZ1 blocked heteromeric α1/β2/γ2 GABAA receptors, ρ2 GABAA (GABAC), and α2 glycine receptors, whereas switching the compound into cis-state by UV illumination restored the activity. Azo-NZ1 successfully photomodulated GABAergic currents recorded from dentate gyrus neurons. We demonstrated that in trans-configuration, Azo-NZ1 blocks the Cl-selective ion pore of GABA receptors interacting mainly with the 2′ level of the TM2 region. CONCLUSIONS AND IMPLICATIONS: Azo-NZ1 is a soluble light-driven Cl-channel blocker, which allows photo-modulation of the activity induced by anion-selective Cys-loop receptors. Azo-NZ1 is able to control GABAergic postsynaptic currents and provides new opportunities to study inhibitory neurotransmission using patterned illumination.


Roux, Anabel-Lise Lee, Quiroga, Xarxa, Walani, Nikhil, Arroyo, Marino, Roca-Cusachs, Pere, (2019). The plasma membrane as a mechanochemical transducer Philosophical Transactions of the Royal Society B: Biological Sciences 374, (1779), 20180221

Cells are constantly submitted to external mechanical stresses, which they must withstand and respond to. By forming a physical boundary between cells and their environment that is also a biochemical platform, the plasma membrane (PM) is a key interface mediating both cellular response to mechanical stimuli, and subsequent biochemical responses. Here, we review the role of the PM as a mechanosensing structure. We first analyse how the PM responds to mechanical stresses, and then discuss how this mechanical response triggers downstream biochemical responses. The molecular players involved in PM mechanochemical transduction include sensors of membrane unfolding, membrane tension, membrane curvature or membrane domain rearrangement. These sensors trigger signalling cascades fundamental both in healthy scenarios and in diseases such as cancer, which cells harness to maintain integrity, keep or restore homeostasis and adapt to their external environment.

Keywords: Plasma membrane, Mechanotransduction, Membrane tension, Mechanosensor


de la Mata, Ana, Mateos-Timoneda, Miguel A., Nieto-Miguel, Teresa, Galindo, Sara, López-Paniagua, Marina, Planell, Josep A., Engel, Elisabeth, Calonge, Margarita, (2019). Poly-l/dl-lactic acid films functionalized with collagen IV as carrier substrata for corneal epithelial stem cells Colloids and Surfaces B: Biointerfaces 177, 121-129

Limbal epithelial stem cells (LESCs) are responsible for the renewal of corneal epithelium. Cultivated limbal epithelial transplantation is the current treatment of choice for restoring the loss or dysfunction of LESCs. To perform this procedure, a substratum is necessary for in vitro culturing of limbal epithelial cells and their subsequent transplantation onto the ocular surface. In this work, we evaluated poly-L/DL-lactic acid 70:30 (PLA) films functionalized with type IV collagen (col IV) as potential in vitro carrier substrata for LESCs. We first demonstrated that PLA-col IV films were biocompatible and suitable for the proliferation of human corneal epithelial cells. Subsequently, limbal epithelial cell suspensions, isolated from human limbal rings, were cultivated using culture medium that did not contain animal components. The cells adhered significantly faster to PLA-col IV films than to tissue culture plastic (TCP). The mRNA expression levels for the LESC specific markers, K15, P63α and ABCG2 were similar or greater (significantly in the case of K15) in limbal epithelial cells cultured on PLA-col IV films than limbal epithelial cells cultured on TCP. The percentage of cells expressing the corneal (K3, K12) and the LESC (P63α, ABCG2) specific markers was similar for both substrata. These results suggest that the PLA-col IV films promoted LESC attachment and helped to maintain their undifferentiated stem cell phenotype. Consequently, these substrata offer an alternative for the transplantation of limbal cells onto the ocular surface.

Keywords: Corneal epithelium, Collagen IV, Limbal stem cells, Polylactic acid, Tissue engineering


Stover, Elizabeth H., Baco, Maria B., Cohen, Ofir, Li, Yvonne Y., Christie, Elizabeth L., Bagul, Mukta, Goodale, Amy, Lee, Yenarae, Pantel, Sasha, Rees, Matthew G., Wei, Guo, Presser, Adam G., Gelbard, Maya K., Zhang, Weiqun, Zervantonakis, Ioannis K., Bhola, Patrick D., Ryan, Jeremy, Guerriero, Jennifer L., Montero, Joan, Liang, Felice J., Cherniack, Andrew D., Piccioni, Federica, Matulonis, Ursula A., Bowtell, David D. L., Sarosiek, Kristopher A., Letai, Anthony, Garraway, Levi A., Johannessen, Cory M., Meyerson, Matthew, (2019). Pooled genomic screens identify anti-apoptotic genes as targetable mediators of chemotherapy resistance in ovarian cancer Molecular Cancer Research 17, (11), 2281-2293

High-grade serous ovarian cancer (HGSOC) is often sensitive to initial treatment with platinum and taxane combination chemotherapy, but most patients relapse with chemotherapy-resistant disease. To systematically identify genes modulating chemotherapy response, we performed pooled functional genomic screens in HGSOC cell lines treated with cisplatin, paclitaxel, or cisplatin plus paclitaxel. Genes in the intrinsic pathway of apoptosis were among the top candidate resistance genes in both gain-of-function and loss-of-function screens. In an open reading frame overexpression screen, followed by a mini-pool secondary screen, anti-apoptotic genes including BCL2L1 (BCL-XL) and BCL2L2 (BCL-W) were associated with chemotherapy resistance. In a CRISPR-Cas9 knockout screen, loss of BCL2L1 decreased cell survival whereas loss of proapoptotic genes promoted resistance. To dissect the role of individual anti-apoptotic proteins in HGSOC chemotherapy response, we evaluated overexpression or inhibition of BCL-2, BCL-XL, BCL-W, and MCL1 in HGSOC cell lines. Overexpression of anti-apoptotic proteins decreased apoptosis and modestly increased cell viability upon cisplatin or paclitaxel treatment. Conversely, specific inhibitors of BCL-XL, MCL1, or BCL-XL/BCL-2, but not BCL-2 alone, enhanced cell death when combined with cisplatin or paclitaxel. Anti-apoptotic protein inhibitors also sensitized HGSOC cells to the poly (ADP-ribose) polymerase inhibitor olaparib. These unbiased screens highlight anti-apoptotic proteins as mediators of chemotherapy resistance in HGSOC, and support inhibition of BCL-XL and MCL1, alone or combined with chemotherapy or targeted agents, in treatment of primary and recurrent HGSOC.Implications: Anti-apoptotic proteins modulate drug resistance in ovarian cancer, and inhibitors of BCL-XL or MCL1 promote cell death in combination with chemotherapy.


Manca, M. L., Lattuada, D., Valenti, D., Marelli, O., Corradini, C., Fernàndez-Busquets, X., Zaru, M., Maccioni, A. M., Fadda, A. M., Manconi, M., (2019). Potential therapeutic effect of curcumin loaded hyalurosomes against inflammatory and oxidative processes involved in the pathogenesis of rheumatoid arthritis: The use of fibroblast-like synovial cells cultured in synovial fluid European Journal of Pharmaceutics and Biopharmaceutics 136, 84-92

In the present work curcumin loaded hyalurosomes were proposed as innovative systems for the treatment of rheumatoid arthritis. Vesicles were prepared using a one-step and environmentally friendly method. Aiming at finding the most suitable formulation in terms of size, surface charge and stability on storage, an extensive pre-formulation study was performed using different type and amount of phospholipids. Curcumin loaded vesicles prepared with 180 mg/ml of Phospholipon 90G (P90G) and immobilized with sodium hyaluronate (2 mg/ml) were selected because of their small size (189 nm), homogeneous dispersion (PI 0.24), negative charge (−35 mV), suitable ability to incorporate high amount of curcumin (E% 88%) and great stability on storage. The in vitro study using fibroblast-like synovial cells cultured in synovial fluid, demonstrated the ability of these vesicles to downregulate the production of anti-apoptotic proteins IAP1 and IAP2 and stimulate the production of IL-10, while the production of IL-6 and IL-15 and reactive oxygen species was reduced, confirming their suitability in counteracting pathogenesis of rheumatoid arthritis.

Keywords: Curcumin, IL-6 and IL-15, In vitro inflammation, Oxidative stress, Phospholipid vesicles, Synoviocytes


Hervera, A., Zhou, L., Palmisano, I., McLachlan, E., Kong, G., Hutson, T. H., Danzi, M. C., Lemmon, V. P., Bixby, J. L., Matamoros-Angles, A., Forsberg, K., De Virgiliis, F., Matheos, D. P., Kwapis, J., Wood, M. A., Puttagunta, R., del Río, J. A., Di Giovanni, S., (2019). PP4-dependent HDAC3 dephosphorylation discriminates between axonal regeneration and regenerative failure EMBO Journal 38, (13), e101032

The molecular mechanisms discriminating between regenerative failure and success remain elusive. While a regeneration-competent peripheral nerve injury mounts a regenerative gene expression response in bipolar dorsal root ganglia (DRG) sensory neurons, a regeneration-incompetent central spinal cord injury does not. This dichotomic response offers a unique opportunity to investigate the fundamental biological mechanisms underpinning regenerative ability. Following a pharmacological screen with small-molecule inhibitors targeting key epigenetic enzymes in DRG neurons, we identified HDAC3 signalling as a novel candidate brake to axonal regenerative growth. In vivo, we determined that only a regenerative peripheral but not a central spinal injury induces an increase in calcium, which activates protein phosphatase 4 that in turn dephosphorylates HDAC3, thus impairing its activity and enhancing histone acetylation. Bioinformatics analysis of ex vivo H3K9ac ChIPseq and RNAseq from DRG followed by promoter acetylation and protein expression studies implicated HDAC3 in the regulation of multiple regenerative pathways. Finally, genetic or pharmacological HDAC3 inhibition overcame regenerative failure of sensory axons following spinal cord injury. Together, these data indicate that PP4-dependent HDAC3 dephosphorylation discriminates between axonal regeneration and regenerative failure.

Keywords: Calcium, HDAC3, Nerve regeneration, Spinal cord injury, Transcription


Hernández-Gea, V., Procopet, B., Giráldez, Á, Amitrano, L., Villanueva, C., Thabut, D., Ibañez-Samaniego, L., Silva-Junior, G., Martinez, J., Genescà, J., Bureau, C., Trebicka, J., Llop, E., Laleman, W., Palazon, J. M., Castellote, J., Rodrigues, S., Gluud, L. L., Noronha Ferreira, C., Barcelo, R., Cañete, N., Rodríguez, M., Ferlitsch, A., Mundi, J. L., Gronbaek, H., Hernández-Guerra, M., Sassatelli, R., Dell'Era, A., Senzolo, M., Abraldes, J. G., Romero-Gómez, M., Zipprich, A., Casas, M., Masnou, H., Primignani, M., Krag, A., Nevens, F., Calleja, J. L., Jansen, C., Robic, M. A., Conejo, I., Catalina, M. V., Albillos, A., Rudler, M., Alvarado, E., Guardascione, M. A., Tantau, M., Bosch, J., Torres, F., Garcia-Pagán, J. C., (2019). Preemptive-TIPS improves outcome in high-risk variceal bleeding: An observational study Hepatology 69, (1), 282-293

Patients admitted with acute variceal bleeding (AVB) and Child-Pugh C score (CP-C) or Child-Pugh B plus active bleeding at endoscopy (CP-B+AB) are at high risk for treatment failure, rebleeding, and mortality. A preemptive transjugular intrahepatic portosystemic shunt (p-TIPS) has been shown to improve survival in these patients, but its use in clinical practice has been challenged and not routinely incorporated. The present study aimed to further validate the role of preemptive TIPS in a large number of high-risk patients. This multicenter, international, observational study included 671 patients from 34 centers admitted for AVB and high risk of treatment failure. Patients were managed according to current guidelines, and use of drugs and endoscopic therapy (D+E) or p-TIPS was based on individual center policy. p-TIPS in the setting of AVB is associated with a lower mortality in CP-C patients compared with D+E (1 year mortality 22% vs. 47% in D+E group; P = 0.002). Mortality rate in CP-B+AB patients was low, and p-TIPS did not improve it. In CP-C and CP-B+AB patients, p-TIPS reduced treatment failure and rebleeding (1-year cumulative incidence function probability of remaining free of the composite endpoint: 92% vs. 74% in the D+E group; P = 0.017) and development of de novo or worsening of previous ascites without increasing rates of hepatic encephalopathy. Conclusion: p-TIPS must be the treatment of choice in CP-C patients with AVB. Because of the strong benefit in preventing further bleeding and ascites, p-TIPS could be a good treatment strategy for CP-B+AB patients..


Maier, Martina, Ballester, Belén Rubio, Verschure, P., (2019). Principles of neurorehabilitation after stroke based on motor learning and brain plasticity mechanisms Frontiers in Systems Neuroscience 13, 74

What are the principles underlying effective neurorehabilitation? The aim of neurorehabilitation is to exploit interventions based on human and animal studies about learning and adaptation, as well as to show that the activation of experience-dependent neuronal plasticity augments functional recovery after stroke. Instead of teaching compensatory strategies that do not reduce impairment but allow the patient to return home as soon as possible, functional recovery might be more sustainable as it ensures a long-term reduction in impairment and an improvement in quality of life. At the same time, neurorehabilitation permits the scientific community to collect valuable data, which allows inferring about the principles of brain organization. Hence neuroscience sheds light on the mechanisms of learning new functions or relearning lost ones. However, current rehabilitation methods lack the exact operationalization of evidence gained from skill learning literature, leading to an urgent need to bridge motor learning theory and present clinical work in order to identify a set of ingredients and practical applications that could guide future interventions. This work aims to unify the neuroscientific literature relevant to the recovery process and rehabilitation practice in order to provide a synthesis of the principles that constitute an effective neurorehabilitation approach. Previous attempts to achieve this goal either focused on a subset of principles or did not link clinical application to the principles of motor learning and recovery. We identified 15 principles of motor learning based on existing literature: massed practice, spaced practice, dosage, task-specific practice, goal-oriented practice, variable practice, increasing difficulty, multisensory stimulation, rhythmic cueing, explicit feedback/knowledge of results, implicit feedback/knowledge of performance, modulate effector selection, action observation/embodied practice, motor imagery, and social interaction. We comment on trials that successfully implemented these principles and report evidence from experiments with healthy individuals as well as clinical work.

Keywords: Neurorehabilitation, Motor learning, Plasticity, Stroke, Principles


Abraldes, J. G., Trebicka, J., Chalasani, N., D'Amico, G., Rockey, D. C., Shah, V. H., Bosch, J., Garcia-Tsao, G., (2019). Prioritization of therapeutic targets and trial design in cirrhotic portal hypertension Hepatology 69, (3), 1287-1299

Portal hypertension (PH) is the main driver of cirrhosis decompensation, the main determinant of death in patients with cirrhosis. PH results initially from increased intrahepatic vascular resistance. Subsequently, increased inflow from splanchnic vasodilation and increased cardiac output lead to a further increase in portal pressure (PP). Reducing PP in cirrhosis results in better outcomes. Removing the cause of cirrhosis might improve PP. However, this is a slow process and patients may continue to be at risk of decompensation. Additionally, for some chronic liver diseases, such as nonalcoholic fatty liver disease (NAFLD), etiological treatments are not yet available. Therefore, there is a need to develop better therapies specifically aimed at reducing PP. For over 35 years, the mainstay of such therapy has been the use of nonselective beta-blockers (NSBBs) that act by reducing portal venous inflow. Recently, many drugs (mainly targeting intrahepatic mechanisms) have shown promise in preclinical and early clinical studies and may act alone or synergistically with NSBBs in reducing PP in cirrhosis. The objective of this position paper is to propose a novel framework for the design of clinical trials (phase 1, 2, and 3) in patients with cirrhosis and PH and to prioritize targets and pharmacological therapies in this setting. We have focused the discussion on patients with compensated cirrhosis. The paper summarizes discussions held at The American Association for the Study of Liver Diseases (AASLD) Industry Colloquium in January 2018, with the participation of clinical and translational investigators, regulatory professionals, and industry partners.


Labay, C., Hamouda, I., Tampieri, F., Ginebra, M. P., Canal, C., (2019). Production of reactive species in alginate hydrogels for cold atmospheric plasma-based therapies Scientific Reports 9, (1), 16160

In the last years, great advances have been made in therapies based in cold atmospheric plasmas (CAP). CAP generate reactive oxygen and nitrogen species (RONS) which can be transferred to liquids. These CAP activated liquids display the same biological efficacy (i.e. on killing cancer cells) as CAP themselves, opening the door for minimally invasive therapies. However, injection of a liquid in the body results in fast diffusion due to extracellular fluids and blood flow. Therefore, the development of efficient vehicles which allow local confinement and delivery of RONS to the diseased site is a fundamental requirement. In this work, we investigate the generation of RONS (H2O2, NO2−, short-lived RONS) in alginate hydrogels by comparing two atmospheric pressure plasma jets: kINPen and a helium needle, at a range of plasma treatment conditions (time, gas flow, distance to the sample). The physic-chemical properties of the hydrogels remain unchanged by the plasma treatment, while the hydrogel shows several-fold larger capacity for generation of RONS than a typical isotonic saline solution. Part of the RONS are quickly released to a receptor media, so special attention has to be put on the design of hydrogels with in-situ crosslinking. Remarkably, the hydrogels show capacity for sustained release of the RONS. The plasma-treated hydrogels remain fully biocompatible (due the fact that the species generated by plasma are previously washed away), indicating that no cytotoxic modifications have occurred on the polymer. Moreover, the RONS generated in alginate solutions showed cytotoxic potential towards bone cancer cells. These results open the door for the use of hydrogel-based biomaterials in CAP-associated therapies.

Keywords: Biomedical materials, Plasma physics


Garcia-Puig, A., Mosquera, J. L., Jiménez-Delgado, S., García-Pastor, C., Jorba, I., Navajas, D., Canals, F., Raya, A., (2019). Proteomics analysis of extracellular matrix remodeling during zebrafish heart regeneration Molecular & cellular proteomics 18, (9), 1745-1755

Adult zebrafish, in contrast to mammals, are able to regenerate their hearts in response to injury or experimental amputation. Our understanding of the cellular and molecular bases that underlie this process, although fragmentary, has increased significantly over the last years. However, the role of the extracellular matrix (ECM) during zebrafish heart regeneration has been comparatively rarely explored. Here, we set out to characterize the ECM protein composition in adult zebrafish hearts, and whether it changed during the regenerative response. For this purpose, we first established a decellularization protocol of adult zebrafish ventricles that significantly enriched the yield of ECM proteins. We then performed proteomic analyses of decellularized control hearts and at different times of regeneration. Our results show a dynamic change in ECM protein composition, most evident at the earliest (7 days post-amputation) time-point analyzed. Regeneration associated with sharp increases in specific ECM proteins, and with an overall decrease in collagens and cytoskeletal proteins. We finally tested by atomic force microscopy that the changes in ECM composition translated to decreased ECM stiffness. Our cumulative results identify changes in the protein composition and mechanical properties of the zebrafish heart ECM during regeneration.

Keywords: Animal models, Atomic force microscopy, Cardiovascular disease, Cardiovascular function or biology, Developmental biology, Extracellular matrix, Heart regeneration, Proteomic analysis


Caballero, David, Pinto, Inês Mendes, Rubinstein, Boris Y., Samitier, Josep, (2019). Protrusion membrane pearling emerges during 3D cell division Physical Biology 16, (6), 066009

Cell division is accompanied by dramatic changes in shape that ultimately lead to the physical separation of one cell into two. In 2D microenvironments, cells round up and remain adhered onto the substrate by thin retraction fibers during division. In contrast, in 3D environments, cells divide exhibiting long protrusions that guide the orientation of the division axis. However, the mechanism of cell division in three dimensions still remains poorly understood. Here we report the spontaneous formation of transient quasiperiodic membrane pearling on extended mitotic protrusions during 3D cell division. Protrusion membrane pearling may be initiated by the non-uniform distribution of focal adhesions and consequent stationary instability of the protrusive membrane. Overall, membrane pearling emergence may provide insights into a novel modality of 3D cell division with potential physiological relevance.


Caballero, David, Pinto, Ines, Rubinstein, Boris, Samitier, Josep, (2019). Protrusion membrane pearling emerges during three-dimensional cell division Physical Biology 16, (6), 066009

Cell division is accompanied by dramatic changes in shape that ultimately lead to the physical separation of one cell into two. In two-dimensional microenvironments, cells round up and remain adhered onto the substrate by thin retraction fibers during division. In contrast, in three-dimensional environments, cells divide exhibiting long protrusions that guide the orientation of the division axis. However, the mechanism of cell division in three dimensions still remains poorly understood. Here we report the spontaneous formation of transient quasiperiodic membrane pearling on extended mitotic protrusions during three-dimensional cell division. Protrusion membrane pearling may be initiated by the non-uniform distribution of focal adhesions and consequent stationary instability of the protrusive membrane. Overall, membrane pearling emergence may provide insights into a novel modality of three-dimensional cell division with potential physiological relevance.


Marban, A., Srinivasan, V., Samek, W., Fernández, J., Casals, A., (2019). A recurrent convolutional neural network approach for sensorless force estimation in robotic surgery Biomedical Signal Processing and Control 50, 134-150

Providing force feedback as relevant information in current Robot-Assisted Minimally Invasive Surgery systems constitutes a technological challenge due to the constraints imposed by the surgical environment. In this context, force estimation techniques represent a potential solution, enabling to sense the interaction forces between the surgical instruments and soft-tissues. Specifically, if visual feedback is available for observing soft-tissues’ deformation, this feedback can be used to estimate the forces applied to these tissues. To this end, a force estimation model, based on Convolutional Neural Networks and Long-Short Term Memory networks, is proposed in this work. This model is designed to process both, the spatiotemporal information present in video sequences and the temporal structure of tool data (the surgical tool-tip trajectory and its grasping status). A series of analyses are carried out to reveal the advantages of the proposal and the challenges that remain for real applications. This research work focuses on two surgical task scenarios, referred to as pushing and pulling tissue. For these two scenarios, different input data modalities and their effect on the force estimation quality are investigated. These input data modalities are tool data, video sequences and a combination of both. The results suggest that the force estimation quality is better when both, the tool data and video sequences, are processed by the neural network model. Moreover, this study reveals the need for a loss function, designed to promote the modeling of smooth and sharp details found in force signals. Finally, the results show that the modeling of forces due to pulling tasks is more challenging than for the simplest pushing actions.

Keywords: Convolutional neural networks, Force estimation, LSTM networks, Robotic surgery


Ferrer, I., Zelaya, M. V., Aguiló García, M., Carmona, M., López-González, I., Andrés-Benito, P., Lidón, L., Gavín, R., Garcia-Esparcia, P., del Rio, J. A., (2019). Relevance of host tau in tau seeding and spreading in tauopathies Brain Pathology Early View

Human tau seeding and spreading occur following intracerebral inoculation of brain homogenates obtained from tauopathies in transgenic mice expressing natural or mutant tau, and in wild-type (WT) mice. The present study was geared to learning about the patterns of tau seeding, the cells involved and the characteristics of tau following intracerebral inoculation of homogenates from primary age-related tauopathy (PART: neuronal 4Rtau and 3Rtau), aging-related tau astrogliopathy (ARTAG: astrocytic 4Rtau) and globular glial tauopathy (GGT: 4Rtau with neuronal deposits and specific tau inclusions in astrocytes and oligodendrocytes). For this purpose, young and adult WT mice were inoculated unilaterally in the hippocampus or in the lateral corpus callosum with sarkosyl-insoluble fractions from PART, ARTAG and GGT cases, and were killed at variable periods of three to seven months. Brains were processed for immunohistochemistry in paraffin sections. Tau seeding occurred in the ipsilateral hippocampus and corpus callosum and spread to the septal nuclei, periventricular hypothalamus and contralateral corpus callosum, respectively. Tau deposits were mainly found in neurons, oligodendrocytes and threads; the deposits were diffuse or granular, composed of phosphorylated tau, tau with abnormal conformation and 3Rtau and 4Rtau independently of the type of tauopathy. Truncated tau at the aspartic acid 421 and ubiquitination were absent. Tau deposits had the characteristics of pre-tangles. A percentage of intracellular tau deposits co-localized with active (phosphorylated) tau kinases p38 and ERK 1/2. Present study shows that seeding and spreading of human tau into the brain of WT mice involves neurons and glial cells, mainly oligodendrocytes, thereby supporting the idea of a primary role of oligodendrogliopathy, together with neuronopathy, in the progression of tauopathies. In addition, it suggests that human tau inoculation modifies murine tau metabolism with the production and deposition of 3Rtau and 4Rtau, and by activation of specific tau kinases in affected cells.

Keywords: Aging-related tau astrogliopathy, Globular glial tauopathy, Primary age-related tauopathy, Seeding, Spreading, Tau, Tauopathies


Rubio Ballester, Belen, Duff, Armin, Maier, Martina, Cameirao, Monica, Bermudez, Sergi, Duarte, Esther, Cuxart, Ampar, Rodriguez, Susana, Verschure, Paul F. M. J., (2019). Revealing an extended critical window of recovery post-stroke bioRxiv (pre-print server) , 458745

The impact of rehabilitation on post-stroke motor recovery and its dependency on the patient's chronicity remain unclear. The existence and regularity of a, so called, proportional recovery rule across a range of functional deficits and therapies supports the notion that functional interventions have little or no impact beyond spontaneous recovery rates in a 'critical window of recovery' which lasts from 3 to 6 months post-stroke. In this meta-analysis, we apply a bootstrap analysis method to assess the overall impact of a specific VR-based rehabilitation protocol for the upper extremities on a homogeneous sample of 219 individuals with hemiparesis at various stages post stroke. Our analysis uncovers a precise gradient of sensitivity to treatment that expands more than one year beyond the limits of the so-called 'critical window of recovery'. These findings redefine the limits of the so-called 'critical window of recovery' and suggest that stroke-derived plasticity mechanisms do facilitate functional recovery even at the chronic and late chronic stage.


Pittolo, Silvia, Lee, Hyojung, Lladó, Anna, Tosi, Sébastien, Bosch, Miquel, Bardia, Lídia, Gómez-Santacana, Xavier, Llebaria, Amadeu, Soriano, Eduardo, Colombelli, Julien, Poskanzer, Kira E., Perea, Gertrudis, Gorostiza, Pau, (2019). Reversible silencing of endogenous receptors in intact brain tissue using two-photon pharmacology Proceedings of the National Academy of Sciences of the United States of America 116, (27), 13680-13689

The physiological activity of proteins is often studied with loss-of-function genetic approaches, but the corresponding phenotypes develop slowly and can be confounding. Photopharmacology allows direct, fast, and reversible control of endogenous protein activity, with spatiotemporal resolution set by the illumination method. Here, we combine a photoswitchable allosteric modulator (alloswitch) and 2-photon excitation using pulsed near-infrared lasers to reversibly silence metabotropic glutamate 5 (mGlu5) receptor activity in intact brain tissue. Endogenous receptors can be photoactivated in neurons and astrocytes with pharmacological selectivity and with an axial resolution between 5 and 10 µm. Thus, 2-photon pharmacology using alloswitch allows investigating mGlu5-dependent processes in wild-type animals, including synaptic formation and plasticity, and signaling pathways from intracellular organelles.

Keywords: Photopharmacology, Photoactivation, Pharmacological selectivity, Functional silencing, 2-photon pharmacology


Guillem-Marti, J., Gelabert, M., Heras-Parets, A., Pegueroles, M., Ginebra, M. P., Manero, J. M., (2019). RGD mutation of the heparin binding II fragment of fibronectin for guiding mesenchymal stem cell behavior on titanium surfaces ACS Applied Materials and Interfaces 11, (4), 3666-3678

Installing bioactivity on metallic biomaterials by mimicking the extracellular matrix (ECM) is crucial for stimulating specific cellular responses to ultimately promote tissue regeneration. Fibronectin is an ECM protein commonly used for biomaterial functionalization. The use of fibronectin recombinant fragments is an attractive alternate to the use of full-length fibronectin because of the relatively low cost and facility of purification. However, it is necessary to combine more than one fragment, for example, the cell attachment site and the heparin binding II (HBII), either mixed or in one molecule, to obtain complete activity. In the present study, we proposed to install adhesion capacity to the HBII fragment by an RGD gain-of-function DNA mutation, retaining its cell differentiation capacity and thereby producing a small and very active protein fragment. The novel molecule, covalently immobilized onto titanium surfaces, maintained the growth factor-binding capacity and stimulated cell spreading, osteoblastic cell differentiation, and mineralization of human mesenchymal stem cells compared to the HBII native protein. These results highlight the potential capacity of gain-of-function DNA mutations in the design of novel molecules for the improvement of osseointegration properties of metallic implant surfaces.

Keywords: Fibronectin, Growth factor, Mutation, Osseointegration, Recombinant protein, Titanium


Klein, S., Frohn, F., Magdaleno, F., Reker-Smit, C., Schierwagen, R., Schierwagen, I., Uschner, F. E., van Dijk, F., Fürst, D. O., Djudjaj, S., Boor, P., Poelstra, K., Beljaars, L., Trebicka, J., (2019). Rho-kinase inhibitor coupled to peptide-modified albumin carrier reduces portal pressure and increases renal perfusion in cirrhotic rats Scientific Reports 9, (1), 2256

Rho-kinase (ROCK) activation in hepatic stellate cells (HSC) is a key mechanism promoting liver fibrosis and portal hypertension (PTH). Specific delivery of ROCK-inhibitor Y-27632 (Y27) to HSC targeting mannose-6-phosphate-receptors reduces portal pressure and fibrogenesis. In decompensated cirrhosis, presence of ascites is associated with reduced renal perfusion. Since in cirrhosis, platelet-derived growth factor receptor beta (PDGFRβ) is upregulated in the liver as well as the kidney, this study coupled Y27 to human serum albumin (HSA) substituted with PDGFRβ-recognizing peptides (pPB), and investigated its effect on PTH in cirrhotic rats. In vitro collagen contraction assays tested biological activity on LX2 cells. Hemodynamics were analyzed in BDL and CCl4 cirrhotic rats 3 h, 6 h and 24 h after i.v. administration of Y27pPBHSA (0.5/1 mg/kg b.w). Phosphorylation of moesin and myosin light chain (MLC) assessed ROCK activity in liver, femoral muscle, mesenteric artery, kidney and heart. Three Y27 molecules were coupled to pPBHSA as confirmed by HPLC/MS, which was sufficient to relax LX2 cells. In vivo, Y27pPBHSA-treated rats exhibited lower portal pressure, hepatic vascular resistance without effect on systemic vascular resistance, but a tendency towards lower cardiac output compared to non-treated cirrhotic rats. Y27pPBHSA reduced intrahepatic resistance by reduction of phosphorylation of moesin and MLC in Y27pPBHSA-treated cirrhotic rats. Y27pPBHSA was found in the liver of rats up to 6 hours after its injection, in the HSC demonstrated by double-immunostainings. Interestingly, Y27pPBHSA increased renal arterial flow over time combined with an antifibrotic effect as shown by decreased renal acta2 and col1a1 mRNA expression. Therefore, targeting the ROCK inhibitor Y27 to PDGFRβ decreases portal pressure with potential beneficial effects in the kidney. This unique approach should be tested in human cirrhosis.

Keywords: Hepatic stellate cells, Hepatorenal syndrome


Praktiknjo, M., Clees, C., Pigliacelli, A., Fischer, S., Jansen, C., Lehmann, J., Pohlmann, A., Lattanzi, B., Krabbe, V. K., Strassburg, C. P., Arroyo, V., Merli, M., Meyer, C., Trebicka, J., (2019). Sarcopenia is associated with development of acute-on-chronic liver failure in decompensated liver cirrhosis receiving transjugular intrahepatic portosystemic shunt Clinical and Translational Gastroenterology 10, (4), e00025

INTRODUCTION: Muscle mass has been shown to be a prognostic marker in patients with liver cirrhosis. Transversal psoas muscle thickness normalized by height (TPMT/height) obtained by routine computed tomography is a simple surrogate parameter for sarcopenia. TPMT/height, however, is not sex specific, which might play a role in risk stratification. Its association with acute-on-chronic liver failure (ACLF) has not been established yet. ACLF is associated with systemic inflammatory dysregulation. This study aimed at evaluating the role of sarcopenia in ACLF development of patients with decompensated cirrhosis receiving transjugular intrahepatic portosystemic shunt (TIPS) using sex-specific TPMT/height. METHODS: One hundred eighty-six patients from the prospective Non-invasive Evaluation Program for TIPS and Follow Up Network cohort (observational, real-world TIPS cohort with structured follow-up) were analyzed. TPMT/height was measured from routine computed tomography. The sex-specific cutoff was determined to classify patients as sarcopenic and nonsarcopenic for 1-year mortality after TIPS. Clinical outcome was compared. Primary end points were ACLF and 1-year mortality after TIPS. Secondary end points were development of decompensations (hepatic encephalopathy and ascites) after TIPS. RESULTS: The sex-specific cutoff increases the diagnostic accuracy with regard to primary and secondary end points compared with the unisex cutoff. Sex-specific sarcopenia classification is an independent predictor of 1-year mortality and ACLF development in patients with cirrhosis receiving TIPS. Patients in the sarcopenia group showed significantly higher rates of mortality, ascites, overt hepatic encephalopathy, and ACLF after TIPS compared with the nonsarcopenia group. The Chronic Liver Failure Consortium Acute Decompensation score as a marker of systemic inflammation was significantly higher in sarcopenic patients. CONCLUSIONS: This study demonstrates for the first time that sarcopenia is related to ACLF development and systemic inflammation. The prognostic value of TPMT/height can be improved by using sex-specific cutoffs.


Grechuta, Klaudia, Ulysse, Laura, Rubio Ballester, Belen, Verschure, Paul, (2019). Self beyond the body: task-relevant distal cues modulate performance and body ownership bioRxiv (pre-print server) , 361022

The understanding of Body Ownership (BO) largely relies on the Rubber Hand Illusion (RHI) where synchronous stroking of real and Rubber Hands (RH) leads to an illusion of ownership of RH provided physical, anatomical, postural and spatial plausibility of the two body-parts. RHI also occurs during visuomotor synchrony, in particular, when the visual feedback of virtual arm movements follows the trajectory of the instantiated motor command. Hence BO seems to result from a bottom-up integration of afferent and efferent proximal multisensory evidence, and top-down prediction of both externally and self-generated signals, which occurs when the predictions about upcoming sensory signals are accurate. In motor control, the differential processing of predicted and actual sensory consequences of self-generated actions is addressed by, the so-called, Forward Model (FM). Based on an efference copy or corollary discharge, FM issues predictions about the sensory consequences of motor commands and compares them with the actual outcome. The discrepancies (Sensory Prediction Errors, SPEs) are used to correct the action on the consecutive trial and provide new estimates of the current state of the body and the environment. Here, we propose that BO might be computed by FMs, and therefore, it might depend on their consistency, specifically, in contexts where the sensory feedback is self-generated. Crucially, to reduce SPE, FMs integrate both proximal (proprioceptive) and distal (vision, audition) sensory cues relevant to the task. Thus, if BO depends on the consistency of FMs, it would be compromised by the incongruency of not only proximal but also distal cues. To test our hypothesis, we devised an embodied VR-based task where action outcomes were signaled by distinct auditory cues. By manipulating the cues with respect to their spatiotemporal congruency and valence, we show that distal feedback which violates predictions about action outcomes compromises both BO and performance. These results demonstrate that BO is influenced by not only efferent and afferent cues which pertain to the body itself but also those arising outside of the body and suggest that in goal-oriented tasks BO might result from a computation of FM.


Xu, D., Wang, Y., Liang, C., You, Y., Sanchez, S., Ma, X., (2019). Self-propelled micro/nanomotors for on-demand biomedical cargo transportation Small Early View

Micro/nanomotors (MNMs) are miniaturized machines that can perform assigned tasks at the micro/nanoscale. Over the past decade, significant progress has been made in the design, preparation, and applications of MNMs that are powered by converting different sources of energy into mechanical force, to realize active movement and fulfill on-demand tasks. MNMs can be navigated to desired locations with precise controllability based on different guidance mechanisms. A considerable research effort has gone into demonstrating that MNMs possess the potential of biomedical cargo loading, transportation, and targeted release to achieve therapeutic functions. Herein, the recent advances of self-propelled MNMs for on-demand biomedical cargo transportation, including their self-propulsion mechanisms, guidance strategies, as well as proof-of-concept studies for biological applications are presented. In addition, some of the major challenges and possible opportunities of MNMs are identified for future biomedical applications in the hope that it may inspire future research.

Keywords: Biomedical applications, Cargo transportation, Guidance strategies, Micro/nanomotors, Self-propulsion


Trebicka, J., Bastgen, D., Byrtus, J., Praktiknjo, M., Terstiegen, S., Meyer, C., Thomas, D., Fimmers, R., Treitl, M., Euringer, W., Sauerbruch, T., Rössle, M., (2019). Smaller-diameter covered transjugular intrahepatic portosystemic shunt stents are associated with increased survival Clinical Gastroenterology and Hepatology 17, (13), 2793-2799.e1

Background & Aims: We studied the effects of diameter of covered, self-expandable, nitinol stents on survival times of patients with a transjugular intrahepatic portosystemic shunt (TIPS). Methods: We collected data from 185 patients (median age, 55 y; 30% female) who received a covered nitinol stent, from February 2006 through September 2010, using the online multicenter German TIPS registry. TIPS were given to 107 patients for refractory ascites and to 78 patients for variceal bleeding. Patients at risk of hepatic encephalopathy (owing to advanced age, prior episodes) or liver failure (bilirubin level, >3 mg/dL), and bleeding patients receiving variceal embolization at TIPS, received 8-mm stents (n = 53). The remaining patients received 10-mm stents (n = 132). Eighty-one of the 10-mm stents were underdilated using 8-mm dilation balloons. Clinical and biochemical data were collected after TIPS placement at 1 month, 3 months, 6 months, 9 months, 1 year, and thereafter every 3 to 6 months. Groups were compared using propensity score analysis. Results: Patients who received 8-mm stents survived significantly longer (34 ± 26 mo) than patients who received 10-mm stents (18 ± 19 mo), regardless of whether they were fully dilated or underdilated. When we compared 10-mm stents with or without underdilation, we found that a significantly higher proportion of patients who received underdilated stents survived for 1 month after TIPS placement (95% vs 84%; P = .03), but not for 3 months (P = .10). In multivariate analysis, 1-year mortality correlated with full dilation of the stent to 10 mm (hazard ratio [HR], 2.0; 95% CI, 1.1–3.5) and with serum creatinine concentration at baseline (HR, 1.5; 95% CI, 1.0–1.7). Five-year mortality was associated with use of the 10-mm stents (HR, 1.8; 95% CI, 1.4–2.7) and baseline concentration of creatinine (HR, 1.3; 95% CI, 1.1–1.6). Conclusions: A smaller stent (nominal diameter of 8 mm, but not underdilation of a 10-mm stent) is associated with a prolonged survival compared with 10-mm stents, independent of liver-specific prognostic criteria.

Keywords: Cirrhosis, Comparison, Covered, Portal Hypertension


Noselli, G., Arroyo, M., DeSimone, A., (2019). Smart helical structures inspired by the pellicle of euglenids Journal of the Mechanics and Physics of Solids 123, 234-246

This paper deals with a concept for a reconfigurable structure bio-inspired by the cell wall architecture of euglenids, a family of unicellular protists, and based on the relative sliding of adjacent strips. Uniform sliding turns a cylinder resulting from the assembly of straight and parallel strips into a cylinder of smaller height and larger radius, in which the strips are deformed into a family of parallel helices. We examine the mechanics of this cylindrical assembly, in which the interlocking strips are allowed to slide freely at their junctions, and compute the external forces (axial force and axial torque at the two ends, or pressure on the lateral surface) necessary to drive and control the shape changes of the composite structure. Despite the simplicity of the structure, we find a remarkably complex mechanical behaviour that can be tuned by the spontaneous curvature or twist of the strips.

Keywords: Bio-inspired structures, Euglenoid pellicle, Helical bundles, Morphing structures, Reconfigurable structures


Burgués, Javier, Hernández, Victor, Lilienthal, Achim J., Marco, Santiago, (2019). Smelling nano aerial vehicle for gas source localization and mapping Sensors 19, (3), 478

This paper describes the development and validation of the currently smallest aerial platform with olfaction capabilities. The developed Smelling Nano Aerial Vehicle (SNAV) is based on a lightweight commercial nano-quadcopter (27 g) equipped with a custom gas sensing board that can host up to two in situ metal oxide semiconductor (MOX) gas sensors. Due to its small form-factor, the SNAV is not a hazard for humans, enabling its use in public areas or inside buildings. It can autonomously carry out gas sensing missions of hazardous environments inaccessible to terrestrial robots and bigger drones, for example searching for victims and hazardous gas leaks inside pockets that form within the wreckage of collapsed buildings in the aftermath of an earthquake or explosion. The first contribution of this work is assessing the impact of the nano-propellers on the MOX sensor signals at different distances to a gas source. A second contribution is adapting the ‘bout’ detection algorithm, proposed by Schmuker et al. (2016) to extract specific features from the derivative of the MOX sensor response, for real-time operation. The third and main contribution is the experimental validation of the SNAV for gas source localization (GSL) and mapping in a large indoor environment (160 m2) with a gas source placed in challenging positions for the drone, for example hidden in the ceiling of the room or inside a power outlet box. Two GSL strategies are compared, one based on the instantaneous gas sensor response and the other one based on the bout frequency. From the measurements collected (in motion) along a predefined sweeping path we built (in less than 3 min) a 3D map of the gas distribution and identified the most likely source location. Using the bout frequency yielded on average a higher localization accuracy than using the instantaneous gas sensor response (1.38 m versus 2.05 m error), however accurate tuning of an additional parameter (the noise threshold) is required in the former case. The main conclusion of this paper is that a nano-drone has the potential to perform gas sensing tasks in complex environments.

Keywords: Robotics, Signal processing, Electronics, Gas source localization, Gas distribution mapping, Gas sensors, Drone, UAV, MOX sensor, Quadcopter


Wickström, S. A., Roca-Cusachs, P., (2019). Special issue on “mechanotransduction in cell fate determination” – From molecular switches to organ-level regulation Experimental Cell Research 382, (1), 111452

Stereotypic formation of tissues requires coordination of cell fate with adhesive and cytoskeletal cues that control cell shape, positioning and motility. The importance of physical ques in shaping development has been demonstrated already a decade ago by observations that their removal arrests embryogenesis. Recent advances in technology and methods to quantify and experimentally manipulate adhesive and mechanical properties of cells and tissues has revolutionized the field. While many aspects of mechanical signaling have been covered by excellent reviews in the past, we invited experts in their respective fields of cell biology and biophysics to review the most recent, exciting breakthroughs on the role of mechanotransduction in cell fate regulation. Amongst these breakthroughs are the advancement of imaging techniques that have allowed single molecule resolution analyses of adhesive structures and quantitative analyses of the mechanical properties of the extracellular matrix and cells, the identification of nucleocytoplasmic transport and ion channels as key players in mechanosensitive cell fate decisions, and the interdisciplinary studies combining physics and biology to understand the role of tension in coupling single cell behaviors to changes in tissue state.


Post, R. A. J., van der Zwaag, D., Bet, G., Wijnands, S. P. W., Albertazzi, L., Meijer, E. W., van der Hofstad, R. W., (2019). A stochastic view on surface inhomogeneity of nanoparticles Nature Communications 10, (1), 1663

The interactions between and with nanostructures can only be fully understood when the functional group distribution on their surfaces can be quantified accurately. Here we apply a combination of direct stochastic optical reconstruction microscopy (dSTORM) imaging and probabilistic modelling to analyse molecular distributions on spherical nanoparticles. The properties of individual fluorophores are assessed and incorporated into a model for the dSTORM imaging process. Using this tailored model, overcounting artefacts are greatly reduced and the locations of dye labels can be accurately estimated, revealing their spatial distribution. We show that standard chemical protocols for dye attachment lead to inhomogeneous functionalization in the case of ubiquitous polystyrene nanoparticles. Moreover, we demonstrate that stochastic fluctuations result in large variability of the local group density between particles. These results cast doubt on the uniform surface coverage commonly assumed in the creation of amorphous functional nanoparticles and expose a striking difference between the average population and individual nanoparticle coverage.


Feiner-Gracia, N., Olea, R. A., Fitzner, R., El Boujnouni, N., Van Asbeck, A. H., Brock, R., Albertazzi, L., (2019). Super-resolution imaging of structure, molecular composition, and stability of single oligonucleotide polyplexes Nano Letters 19, (5), 2784-2792

The successful application of gene therapy relies on the development of safe and efficient delivery vectors. Cationic polymers such as cell-penetrating peptides (CPPs) can condense genetic material into nanoscale particles, called polyplexes, and induce cellular uptake. With respect to this point, several aspects of the nanoscale structure of polyplexes have remained elusive because of the difficulty in visualizing the molecular arrangement of the two components with nanometer resolution. This limitation has hampered the rational design of polyplexes based on direct structural information. Here, we used super-resolution imaging to study the structure and molecular composition of individual CPP-mRNA polyplexes with nanometer accuracy. We use two-color direct stochastic optical reconstruction microscopy (dSTORM) to unveil the impact of peptide stoichiometry on polyplex structure and composition and to assess their destabilization in blood serum. Our method provides information about the size and composition of individual polyplexes, allowing the study of such properties on a single polyplex basis. Furthermore, the differences in stoichiometry readily explain the differences in cellular uptake behavior. Thus, quantitative dSTORM of polyplexes is complementary to the currently used characterization techniques for understanding the determinants of polyplex activity in vitro and inside cells.

Keywords: dSTORM, Gene delivery, Polyplexes, Stability, Super-resolution microscopy


Pujals, S., Feiner-Gracia, N., Delcanale, P., Voets, I., Albertazzi, L., (2019). Super-resolution microscopy as a powerful tool to study complex synthetic materials Nature Reviews Chemistry 3, (2), 68-84

Understanding the relations between the formation, structure, dynamics and functionality of complex synthetic materials is one of the great challenges in chemistry and nanotechnology and represents the foundation for the rational design of novel materials for a variety of applications. Initially conceived to study biology below the diffraction limit, super-resolution microscopy (SRM) is emerging as a powerful tool for studying synthetic materials owing to its nanometric resolution, multicolour ability and minimal invasiveness. In this Review, we provide an overview of the pioneering studies that use SRM to visualize materials, highlighting exciting recent developments such as experiments in operando, wherein materials, such as biomaterials in a biological environment, are imaged in action. Moreover, the potential and the challenges of the different SRM methods for application in nanotechnology and (bio)materials science are discussed, aiming to guide researchers to select the best SRM approach for their specific purpose.

Keywords: Bioinspired materials, Imaging techniques


Pujals, S., Albertazzi, L., (2019). Super-resolution microscopy for nanomedicine research ACS Nano 13, (9), 9707-9712

Super-resolution microscopy, or nanoscopy, revolutionized the field of cell biology, enabling researchers to visualize cellular structures with nanometric resolution, single-molecule sensitivity, and in multiple colors. However, the impact of these techniques goes beyond biology as the fields of nanotechnology and nanomedicine can greatly benefit from them, as well. Nanoscopy can visualize nanostructures in vitro and in cells and can contribute to the characterization of their structures and nano-bio interactions. In this Perspective, we discuss the potential of super-resolution imaging for nanomedicine research, its technical challenges, and the future developments we envision for this technology.


Kolpe, A., Arista-Romero, M., Schepens, B., Pujals, S., Saelens, X., Albertazzi, L., (2019). Super-resolution microscopy reveals significant impact of M2e-specific monoclonal antibodies on influenza A virus filament formation at the host cell surface Scientific Reports 9, (1), 4450

Influenza A virions are highly pleomorphic, exhibiting either spherical or filamentous morphology. The influenza A virus strain A/Udorn/72 (H3N2) produces copious amounts of long filaments on the surface of infected cells where matrix protein 1 (M1) and 2 (M2) play a key role in virus filament formation. Previously, it was shown that an anti-M2 ectodomain (M2e) antibody could inhibit A/Udorn/72 virus filament formation. However, the study of these structures is limited by their small size and complex structure. Here, we show that M2e-specific IgG1 and IgG2a mouse monoclonal antibodies can reduce influenza A/Udorn/72 virus plaque growth and infectivity in vitro. Using Immuno-staining combined with super-resolution microscopy that allows us to study structures beyond the diffraction limit, we report that M2 is localized at the base of viral filaments that emerge from the membrane of infected cells. Filament formation was inhibited by treatment of A/Udorn/72 infected cells with M2e-specific IgG2a and IgG1 monoclonal antibodies and resulted in fragmentation of pre-existing filaments. We conclude that M2e-specific IgGs can reduce filamentous influenza A virus replication in vitro and suggest that in vitro inhibition of A/Udorn/72 virus replication by M2e-specific antibodies correlates with the inhibition of filament formation on the surface of infected cells.


Kaurin, D., Arroyo, M., (2019). Surface tension controls the hydraulic fracture of adhesive interfaces bridged by molecular bonds Physical Review Letters 123, (22), 228102

Biological function requires cell-cell adhesions to tune their cohesiveness; for instance, during the opening of new fluid-filled cavities under hydraulic pressure. To understand the physical mechanisms supporting this adaptability, we develop a stochastic model for the hydraulic fracture of adhesive interfaces bridged by molecular bonds. We find that surface tension strongly enhances the stability of these interfaces by controlling flaw sensitivity, lifetime, and optimal architecture in terms of bond clustering. We also show that bond mobility embrittles adhesions and changes the mechanism of decohesion. Our study provides a mechanistic background to understand the biological regulation of cell-cell cohesion and fracture.

Keywords: Biomimetic & bio-inspired materials, Cell adhesion, Fracture, Self-healing


Noselli, G., Beran, A., Arroyo, M., DeSimone, A., (2019). Swimming Euglena respond to confinement with a behavioural change enabling effective crawling Nature Physics 15, (5), 496-502

Some euglenids, a family of aquatic unicellular organisms, can develop highly concerted, large-amplitude peristaltic body deformations. This remarkable behaviour has been known for centuries. Yet, its function remains controversial, and is even viewed as a functionless ancestral vestige. Here, by examining swimming Euglena gracilis in environments of controlled crowding and geometry, we show that this behaviour is triggered by confinement. Under these conditions, it allows cells to switch from unviable flagellar swimming to a new and highly robust mode of fast crawling, which can deal with extreme geometric confinement and turn both frictional and hydraulic resistance into propulsive forces. To understand how a single cell can control such an adaptable and robust mode of locomotion, we developed a computational model of the motile apparatus of Euglena cells consisting of an active striated cell envelope. Our modelling shows that gait adaptability does not require specific mechanosensitive feedback but instead can be explained by the mechanical self-regulation of an elastic and extended motor system. Our study thus identifies a locomotory function and the operating principles of the adaptable peristaltic body deformation of Euglena cells.


Cabré, Gisela, Garrido-Charles, Aida, González-Lafont, Àngels, Moormann, Widukind, Langbehn, Daniel, Egea, David, Lluch, José M., Herges, Rainer, Alibés, Ramon, Busqué, Félix, Gorostiza, Pau, Hernando, Jordi, (2019). Synthetic photoswitchable neurotransmitters based on bridged azobenzenes Organic Letters 21, (10), 3780-3784

Photoswitchable neurotransmitters of ionotropic kainate receptors were synthesized by tethering a glutamate moiety to disubstituted C2-bridged azobenzenes, which were prepared through a novel methodology that allows access to diazocines with higher yields and versatility. Because of the singular properties of these photochromes, photoisomerizable compounds were obtained with larger thermal stability for their inert cis isomer than for their biologically activity trans state. This enabled selective neuronal firing upon irradiation without background activity in the dark.


De Matteis, Valeria, Cascione, Mariafrancesca, Toma, Chiara Cristina, Pellegrino, Paolo, Rizzello, Loris, Rinaldi, Rosaria, (2019). Tailoring cell morphomechanical perturbations through metal oxide nanoparticles Nanoscale Research Letters 14, (1), 109

The nowadays growing use of nanoparticles (NPs) in commercial products does not match a comprehensive understanding of their potential harmfulness. More in vitro investigations are required to address how the physicochemical properties of NPs guide their engulfment within cells and their intracellular trafficking, fate, and toxicity. These nano-bio interactions have not been extensively addressed yet, especially from a mechanical viewpoint. Cell mechanic is a critical indicator of cell health because it regulates processes like cell migration, tissue integrity, and differentiation via cytoskeleton rearrangements. Here, we investigated in vitro the elasticity perturbation of Caco-2 and A549 cell lines, in terms of Young’s modulus modification induced by SiO2NPS and TiO2NPS. TiO2NPs demonstrated stronger effects on cell elasticity compared to SiO2NPs, as they induced significant morphological and morphometric changes in actin network. TiO2NPS increased the elasticity in Caco-2 cells, while opposite effects have been observed on A549 cells. These results demonstrate the existence of a correlation between the alteration of cell elasticity and NPs toxicity that depends, in turn, on the NPs physicochemical properties and the specific cell tested.


Farré, R., Navajas, D., Gozal, D., Montserrat, J. M., (2019). Telematic multi-physician decision-making for improving CPAP prescription in sleep apnoea Archivos de Bronconeumología Archivos de Bronconeumologia , 55, (11), 604-606

Telematic multi-physician decision-making for improving CPAP prescription in sleep apnoea.


Klein, S., Kleine, C. E., Pieper, A., Granzow, M., Gautsch, S., Himmit, M., Kahrmann, K., Schierwagen, R., Uschner, F. E., Magdaleno, F., Naoum, M. E., Kristiansen, G., Walther, T., Bader, M., Sauerbruch, T., Trebicka, J., (2019). TGR(mREN2)27 rats develop non-alcoholic fatty liver disease-associated portal hypertension responsive to modulations of Janus-kinase 2 and Mas receptor Scientific Reports 9, (1), 11598

Prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Resulting fibrosis and portal hypertension, as a possible secondary event, may necessitate treatment. Overexpression of mouse renin in the transgenic rat model, TGR(mREN2)27, leads to spontaneous development of NAFLD. Therefore, we used TGR(mREN2)27 rats as a model of NAFLD where we hypothesized increased susceptibility and investigated fibrosis and portal hypertension and associated pathways. 12-week old TGR(mREN2)27 rats received either cholestatic (BDL) or toxic injury (CCl4 inhalation). Portal and systemic hemodynamic assessments were performed using microsphere technique with and without injection of the Janus-Kinase 2 (JAK2) inhibitor AG490 or the non-peptidic Ang(1-7) agonist, AVE0991. The extent of liver fibrosis was assessed in TGR(mREN2)27 and wild-type rats using standard techniques. Protein and mRNA levels of profibrotic, renin-angiotensin system components were assessed in liver and primary hepatic stellate cells (HSC) and hepatocytes. TGR(mREN2)27 rats developed spontaneous, but mild fibrosis and portal hypertension due to the activation of the JAK2/Arhgef1/ROCK pathway. AG490 decreased migration of HSC and portal pressure in isolated liver perfusions and in vivo. Fibrosis or portal hypertension after cholestatic (BDL) or toxic injury (CCl4) was not aggravated in TGR(mREN2)27 rats, probably due to decreased mouse renin expression in hepatocytes. Interestingly, portal hypertension was even blunted in TGR(mREN2)27 rats (with or without additional injury) by AVE0991. TGR(mREN2)27 rats are a suitable model of spontaneous liver fibrosis and portal hypertension but not with increased susceptibility to liver damage. After additional injury, the animals can be used to evaluate novel therapeutic strategies targeting Mas.

Keywords: Mechanisms of disease, Molecular medicine


Riera, R., Feiner-Gracia, N., Fornaguera, C., Cascante, A., Borrós, S., Albertazzi, L., (2019). Tracking the DNA complexation state of pBAE polyplexes in cells with super resolution microscopy Nanoscale 11, (38), 17869-17877

The future of gene therapy relies on the development of efficient and safe delivery vectors. Poly(β-amino ester)s are promising cationic polymers capable of condensing oligonucleotides into nanoparticles – polyplexes – and deliver them into the cell nucleus, where the gene material would be expressed. The complexation state during the crossing of biological barriers is crucial: polymers should tightly complex DNA before internalization and then release to allow free DNA to reach the nucleus. However, measuring the complexation state in cells is challenging due to the nanometric size of polyplexes and the difficulties to study the two components (polymer and DNA) independently. Here we propose a method to visualize and quantify the two components of a polyplex inside cells, with nanometre scale resolution, using two-colour direct stochastic reconstruction super-resolution microscopy (dSTORM). With our approach, we tracked the complexation state of pBAE polyplexes from cell binding to DNA release and nuclear entry revealing time evolution and the final fate of DNA and pBAE polymers in mammalian cells.


Uroz, Marina, Garcia-Puig, Anna, Tekeli, Isil, Elosegui-Artola, Alberto, Abenza, Juan F., Marín-Llauradó, Ariadna, Pujals, Silvia, Conte, Vito, Albertazzi, Lorenzo, Roca-Cusachs, Pere, Raya, Ángel, Trepat, Xavier, (2019). Traction forces at the cytokinetic ring regulate cell division and polyploidy in the migrating zebrafish epicardium Nature Materials 18, 1015-1023

Epithelial repair and regeneration are driven by collective cell migration and division. Both cellular functions involve tightly controlled mechanical events, but how physical forces regulate cell division in migrating epithelia is largely unknown. Here we show that cells dividing in the migrating zebrafish epicardium exert large cell–extracellular matrix (ECM) forces during cytokinesis. These forces point towards the division axis and are exerted through focal adhesions that connect the cytokinetic ring to the underlying ECM. When subjected to high loading rates, these cytokinetic focal adhesions prevent closure of the contractile ring, leading to multi-nucleation through cytokinetic failure. By combining a clutch model with experiments on substrates of different rigidity, ECM composition and ligand density, we show that failed cytokinesis is triggered by adhesion reinforcement downstream of increased myosin density. The mechanical interaction between the cytokinetic ring and the ECM thus provides a mechanism for the regulation of cell division and polyploidy that may have implications in regeneration and cancer.


Roki, N., Tsinas, Z., Solomon, M., Bowers, J., Getts, R. C., Muro, S., (2019). Unprecedently high targeting specificity toward lung ICAM-1 using 3DNA nanocarriers Journal of Controlled Release 305, 41-49

DNA nanostructures hold great potential for drug delivery. However, their specific targeting is often compromised by recognition by scavenger receptors involved in clearance. In our previous study in cell culture, we showed targeting specificity of a 180 nm, 4-layer DNA-built nanocarrier called 3DNA coupled with antibodies against intercellular adhesion molecule-1 (ICAM-1), a glycoprotein overexpressed in the lungs in many diseases. Here, we examined the biodistribution of various 3DNA formulations in mice. A formulation consisted of 3DNA whose outer-layer arms were hybridized to secondary antibody-oligonucleotide conjugates. Anchoring IgG on this formulation reduced circulation and kidney accumulation vs. non-anchored IgG, while increasing liver and spleen clearance, as expected for a nanocarrier. Anchoring anti-ICAM changed the biodistribution of this antibody similarly, yet this formulation specifically accumulated in the lungs, the main ICAM-1 target. Since lung targeting was modest (2-fold specificity index over IgG formulation), we pursued a second preparation involving direct hybridization of primary antibody-oligonucleotide conjugates to 3DNA. This formulation had prolonged stability in serum and showed a dramatic increase in lung distribution: the specificity index was 424-fold above a matching IgG formulation, 144-fold more specific than observed for PLGA nanoparticles of similar size, polydispersity, ζ-potential and antibody valency, and its lung accumulation increased with the number of anti-ICAM molecules per particle. Immunohistochemistry showed that anti-ICAM and 3DNA components colocalized in the lungs, specifically associating with endothelial markers, without apparent histological changes. The degree of in vivo targeting for anti-ICAM/3DNA-nanocarriers is unprecedented, for which this platform technology holds great potential to develop future therapeutic applications.

Keywords: 3DNA, DNA nanostructure, Drug nanocarrier, Endothelial and lung targeting, ICAM-1, In vivo biodistribution


Mas, S., Torro, A., Bec, N., Fernández, L., Erschov, G., Gongora, C., Larroque, C., Martineau, P., de Juan, A., Marco, S., (2019). Use of physiological information based on grayscale images to improve mass spectrometry imaging data analysis from biological tissues Analytica Chimica Acta 1074, 69-79

The characterization of cancer tissues by matrix-assisted laser desorption ionization-mass spectrometry images (MALDI-MSI) is of great interest because of the power of MALDI-MS to understand the composition of biological samples and the imaging side that allows for setting spatial boundaries among tissues of different nature based on their compositional differences. In tissue-based cancer research, information on the spatial location of necrotic/tumoral cell populations can be approximately known from grayscale images of the scanned tissue slices. This study proposes as a major novelty the introduction of this physiologically-based information to help in the performance of unmixing methods, oriented to extract the MS signatures and distribution maps of the different tissues present in biological samples. Specifically, the information gathered from grayscale images will be used as a local rank constraint in Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) for the analysis of MALDI-MSI of cancer tissues. The use of this constraint, setting absence of certain kind of tissues only in clear zones of the image, will help to improve the performance of MCR-ALS and to provide a more reliable definition of the chemical MS fingerprint and location of the tissues of interest. The general strategy to address the analysis of MALDI-MSI of cancer tissues will involve the study of the MCR-ALS results and the posterior use of MCR-ALS scores as dimensionality reduction for image segmentation based on K-means clustering. The resolution method will provide the MS signatures and their distribution maps for each tissue in the sample. Then, the resolved distribution maps for each biological component (MCR scores) will be submitted as initial information to K-means clustering for image segmentation to obtain information on the boundaries of the different tissular regions in the samples studied. MCR-ALS prior to K-means not only provides the desired dimensionality reduction, but additionally resolved non-biological signal contributions are not used and the weight given to the different biological components in the segmentation process can be modulated by suitable preprocessing methods.

Keywords: MCR-ALS, K-means, Local rank constraints, MALDI-MSI, Grayscale images


Blanco-Almazan, D., Groenendaal, W., Catthoor, F., Jane, R., (2019). Wearable bioimpedance measurement for respiratory monitoring during inspiratory loading IEEE Access 7, 89487-89496

Bioimpedance is an unobtrusive noninvasive technique to measure respiration and has a linear relation with volume during normal breathing. The objective of this paper was to assess this linear relation during inspiratory loading protocol and determine the best electrode configuration for bioimpedance measurement. The inspiratory load is a way to estimate inspiratory muscle function and has been widely used in studies of respiratory mechanics. Therefore, this protocol permitted us to evaluate bioimpedance performance under breathing pattern changes. We measured four electrode configurations of bioimpedance and airflow simultaneously in ten healthy subjects using a wearable device and a standard wired laboratory acquisition system, respectively. The subjects were asked to perform an incremental inspiratory threshold loading protocol during the measurements. The load values were selected to increase progressively until the 60% of the subject's maximal inspiratory pressure. The linear relation of the signals was assessed by Pearson correlation (r ) and the waveform agreement by the mean absolute percentage error (MAPE), both computed cycle by cycle. The results showed a median greater than 0.965 in r coefficients and lower than 11 % in the MAPE values for the entire population in all loads and configurations. Thus, a strong linear relation was found during all loaded breathing and configurations. However, one out of the four electrode configurations showed robust results in terms of agreement with volume during the highest load. In conclusion, bioimpedance measurement using a wearable device is a noninvasive and a comfortable alternative to classical methods for monitoring respiratory diseases in normal and restrictive breathing.

Keywords: Bioimpedance, Chronic respiratory diseases, Electrode configurations, Inspiratory threshold protocol, Wearable


Manthe, R. L., Rappaport, J. A., Long, Y., Solomon, M., Veluvolu, V., Hildreth, M., Gugutkov, D., Marugan, J., Zheng, W., Muro, S., (2019). δ-Tocopherol effect on endocytosis and its combination with enzyme replacement therapy for lysosomal disorders: A new type of drug interaction? Journal of Pharmacology and Experimental Therapeutics 370, (3), 823-833

Induction of lysosomal exocytosis alleviates lysosomal storage of undigested metabolites in cell models of lysosomal disorders (LDs). However, whether this strategy affects other vesicular compartments, e.g., those involved in endocytosis, is unknown. This is important both to predict side effects and to use this strategy in combination with therapies that require endocytosis for intracellular delivery, such as lysosomal enzyme replacement therapy (ERT). We investigated this using δ-tocopherol as a model previously shown to induce lysosomal exocytosis and cell models of type A Niemann-Pick disease, a LD characterized by acid sphingomyelinase (ASM) deficiency and sphingomyelin storage. δ-Tocopherol and derivative CF3-T reduced net accumulation of fluid phase, ligands, and polymer particles via phagocytic, caveolae-, clathrin-, and cell adhesion molecule (CAM)-mediated pathways, yet the latter route was less affected due to receptor overexpression. In agreement, δ-tocopherol lowered uptake of recombinant ASM by deficient cells (known to occur via the clathrin pathway) and via targeting intercellular adhesion molecule-1 (associated to the CAM pathway). However, the net enzyme activity delivered and lysosomal storage attenuation were greater via the latter route. Data suggest stimulation of exocytosis by tocopherols is not specific of lysosomes and affects endocytic cargo. However, this effect was transient and became unnoticeable several hours after tocopherol removal. Therefore, induction of exocytosis in combination with therapies requiring endocytic uptake, such as ERT, may represent a new type of drug interaction, yet this strategy could be valuable if properly timed for minimal interference.


Rubio Ballester, B., Mura, A., Maier, M., Tobella-Pareja, Laura, Alfayate-Domingo, D., Gimeno-Esteve, M. F., Aguilar, A., Verschure, P., (2019). Adaptive VR-based rehabilitation to prevent deterioration in adults with cerebral palsy Application of VR and Advanced Technology in Pediatric Populations International Conference on Virtual Rehabilitation 2019 (ICVR 2019) , ISVR (Tel Aviv, Israel) , 1-7

Cerebral palsy (CP) is a disabling life-long condition progressively impeding a patient’s independence. Although incident rates are high, a clear understanding of the disease is missing. CP is characterized by several motor disorders and sensory or perceptive comorbidities. This multifaceted nature complicates proper diagnosis and hampers the search for possible treatments. During adolescence and adulthood, individuals with CP experience a drastic deterioration in gross motor control, independence, and quality of life. There is poor evidence that physical therapy promotes the retention of function through aging, and no clinical studies exist that explore the potential of VRbased training to prevent deterioration. In this pilot randomized controlled trial, we expose 14 adults with CP to the Rehabilitation Gaming System (RGS) and examine its usability, effectiveness, and acceptability. Our results show that the RGS difficulty adaptation algorithm automatically matches the patients' impairment level as captured by clinical scales (Barthel and Box & Blocks). The clinical effectiveness and acceptability of the RGS and conventional therapy were comparable. We conclude that VR-based physical therapy as an adjunct to usual treatment may be a promising approach for the prevention of deterioration in adolescents and adults with CP.

Keywords: Cerebral palsy, Virtual realitY, Motor function, Physical therapy, Rehabilitation


Feitosa, J. A., Stefano Filho, C. A., Casseb, R. F., Camargo, A., Martins, B. S. G., Ballester, B. R., Omedas, P., Verschure, P., Oberg, T. D., Min, L. L., Castellano, G., (2019). Complex network changes during a virtual reality rehabilitation protocol following stroke: A case study NER 2019 9th International IEEE/EMBS Conference on Neural Engineering , IEEE (San Francisco, USA) , 891-894

Stroke is one of the main causes of disabilities caused by injuries to the human central nervous system, yielding a wide range of mild to severe impairments that can compromise sensorimotor and cognitive functions. Although rehabilitation protocols may improve function of stroke survivors, patients often reach plateaus while undergoing therapy. Recently, virtual reality (VR) technologies have been paired with traditional rehabilitation aiming to improve function recovery after stroke. Aiming to better understand structural brain changes due to VR rehabilitation protocols, we modeled the brain as a graph and extracted three measures representing the network's topology: degree, clustering coefficient and betweenness centrality (BC). In this single case study, our results indicate that all metrics increased on the ipsilesional hemisphere, while remaining about the same at the contrale-sional site. Particularly, the number of functional connections increased in the lesion area overtime. In addition, the BC displayed the highest variations, and in brain regions related to the patient's cognitive and motor impairments; hence, we argue that this measure could be regarded as an indicative for brain plasticity mechanisms.


Maier, M., Low, S. C., Ballester, B. R., Bañuelos, N. L., Oller, E. D., Verschure, P., (2019). Depression modulates attentional processing after stroke Biosystems & Biorobotics International Conference on NeuroRehabilitation - Converging Clinical and Engineering Research on Neurorehabilitation III , Springer, Cham (Pisa, Italy) 21, 702-706

Depression is a common sequela after stroke and has severe implications on a patient’s life. Post-stroke depression has been linked to cognitive impairment, but the mechanisms that lead to this deficit are not well understood. We tested 18 chronic stroke patients with depression in a psychophysical task to evaluate their attentional processing under varying cognitive loads. We found that the level of depression had no effect on the unconscious, bottom-up components of attentional processing but did influence the top-down ones. These results support the notion that depression might act like an additional cognitive load, impeding the conscious processes and responses although the information has been unconsciously processed.


Mestre, R., Patiño, T., Guix, M., Barceló, X., Sánchez, S., (2019). Design, optimization and characterization of bio-hybrid actuators based on 3D-bioprinted skeletal muscle tissue Biomimetic and Biohybrid Systems 8th International Conference, Living Machines 2019 (Lecture Notes in Computer Science) , Springer International Publishing (Nara, Japan) 11556, 205-215

The field of bio-hybrid robotics aims at the integration of biological components with artificial materials in order to take advantage of many unique features occurring in nature, such as adaptability, self-healing or resilience. In particular, skeletal muscle tissue has been used to fabricate bio-actuators or bio-robots that can perform simple actions. In this paper, we present 3D bioprinting as a versatile technique to develop these kinds of actuators and we focus on the importance of optimizing the designs and properly characterizing their performance. For that, we introduce a method to calculate the force generated by the bio-actuators based on the deflection of two posts included in the bio-actuator design by means of image processing algorithms. Finally, we present some results related to the adaptation, controllability and force modulation of our bio-actuators, paving the way towards a design- and optimization-driven development of more complex 3D-bioprinted bio-actuators.

Keywords: 3D bioprinting, Bio-hybrid robotics, Muscle-based bio-actuators


Vouloutsi, V., Grechuta, K., Verschure, P., (2019). Evaluation of the facial expressions of a humanoid robot Biomimetic and Biohybrid Systems 8th International Conference, Living Machines 2019 (Lecture Notes in Computer Science) , Springer International Publishing (Nara, Japan) 11556, 365-368

Facial expressions are salient social features that crucial in communication, and humans are capable of reading the messages faces convey and the emotions they display. Robots that interact with humans will need to employ similar communication channels for successful interactions. Here, we focus on the readability of the facial expressions of a humanoid robot. We conducted an online survey where participants evaluated emotional stimuli and assessed the robot’s expressions. Results suggest that the robot’s facial expressions are correctly recognised and the appraisal of the robots expressive elements are consistent with the literature.

Keywords: Emotion recognition, Facial expressions, Human-robot interaction


Zalvidea, D., Trepat, X., Rebollo, E., (2019). Fast multiphoton microscope based on polymer ulenses array using a 3D printed mold CL Poster session 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference , IEEE (Munich, Germany) OSA Technical Digest (Optical Society of America, 2019), paper cl_p_22

Multiphoton microscopy is a well-established technique for in vivo tissue imaging at high resolution and long penetration depth. As it uses a single point detector and a single scanning beam, image generation is slow. Several competitive solutions have been proposed during the last years, e.g. resonant scanning, that can reach 30 fps at 2048×2048 scanning resolution but relying on a fixed speed but it does not grant enough time for efficient collection of photons, or multiplexing beams, which show poor efficiency. Here, we propose a multiplexed beam solution that uses a rotating ulenses array for excitation and a camera for detection. The array of ulenses was built in polydimethilsiloxane (PDMS; > 90% transmission in the near IR wavelengths typically used in multiphoton microscopy), using a 3D-printed mold designed following a Nipkow disc pattern slightly modified to increase the lenses efficiency.


Arsiwalla, X. D., Freire, I. T., Vouloutsi, V., Verschure, P., (2019). Latent morality in algorithms and machines Biomimetic and Biohybrid Systems 8th International Conference, Living Machines 2019 (Lecture Notes in Computer Science) , Springer, Cham (Nara, Japan) 11556, 309-315

Can machines be endowed with morality? We argue that morality in the descriptive or epistemic sense can be extended to artificial systems. Following arguments from evolutionary game-theory, we identify two main ingredients required to operationalize this notion of morality in machines. The first, being a group theory of mind, and the second, being an assignment of valence. We make the case for the plausibility of these operations in machines without reference to any form of intentionality or consciousness. The only systems requirements needed to support the above two operations are autonomous goal-directed action and the ability to interact and learn from the environment. Following this we have outlined a theoretical framework based on conceptual spaces and valence assignments to gauge latent morality in autonomous machines and algorithms.

Keywords: Autonomous systems, Ethics of algorithms, Goal-directed action, Philosophy of morality, Qualia, Theory of mind


Matera, C., Gomila, A. M. J., Camarero, N., Libergoli, M., Soler, C., Gorostiza, P., (2019). Photochromic antifolate for light-activated chemotherapy Proceedings of SPIE 17th International Photodynamic Association World Congress , SPIE (Cambridge, USA) 11070, 110709H

Although cytotoxic chemotherapy is one of the primary pharmacological treatments for chronic hyperproliferative diseases such as cancer and psoriasis, its efficacy and tolerability are in many cases dramatically limited by off-target toxicity. A promising approach to improve these therapies is to activate the drugs exclusively at their desired place of action. In fact, in those diseases that would benefit from a highly localized treatment, a precise spatiotemporal control over the activity of a chemotherapeutic agent would allow reducing the concentration of active compound outside the targeted region, improving the tolerability of the treatment. Light is a powerful tool in this respect: it offers unparalleled opportunities as a non-invasive regulatory signal for pharmacological applications because it can be delivered with high precision regarding space, time, intensity and wavelength. Photopharmacology represents a new and emerging approach in this regard since the energy of light is used to change the structure of the drug and hence to switch its pharmacological activity on and off on demand. We describe here phototrexate, the first light-regulated inhibitor of the human DHFR. Enzyme and cell viability assays demonstrated that phototrexate behaves as a potent antifolate in its cis configuration, obtained under UVA illumination, and that it is nearly inactive in its dark-relaxed trans form. Experiments in zebrafish confirmed that phototrexate can disrupt folate metabolism in a light-dependent fashion also in vivo. Overall, phototrexate represents a potential candidate towards the development of an innovative photoactivated antifolate chemotherapy.

Keywords: Cancer, Dermatology, Methotrexate, Photoactivated chemotherapy, Photodynamic therapy, Phototherapy, Psoriasis, Rheumatoid arthritis


Amil, A. F., Maffei, G., Puigbò, J. Y., Arsiwalla, X. D., Verschure, P., (2019). Robust postural stabilization with a biomimetic hierarchical control architecture Biomimetic and Biohybrid Systems 8th International Conference, Living Machines 2019 (Lecture Notes in Computer Science) , Springer, Cham (Nara, Japan) 11556, 321-324

Fast online corrections during anticipatory movements are a signature of robustness in biological motor control. In this regard, a previous study suggested that anticipatory postural control can be recast as a sensory-sensory predictive process, where hierarchically connected cerebellar microcircuits reflect the causal sequence of events preceding a postural disturbance. Hence, error monitoring signals from higher sensory layers inform lower layers about violations of expectations, affording fast corrections when the normal sequence is broken. Here we generalize this insight and prove that the proposed hierarchical control architecture can deal with different types of alterations in the causal structure of the environment, therefore extending the limits of performance.

Keywords: Anticipatory control, Cerebellum, Control architecture, Robustness


Rodríguez-Cañón, M., Delgado, I., Jané, R., García-Alñías, G., (2019). Temporal categorization of upper limb muscle’s EMG activity during reaching and grasping Biosystems and Biorobotics International Conference on NeuroRehabilitation - Converging Clinical and Engineering Research on Neurorehabilitation III , Springer, Cham (Pisa, Italy) 21, 876-879

We describe the data processing employed to match EMG signals with the categorized behavioral movements obtained from video recordings in awake rats while reaching and grasping pellets. We want to determine whether or not, the forelimb muscles follow a temporal synchronized pattern of activity during reaching and grasping. Data processing included raw data filtering and obtaining the first derivate. We found consistency in this procedure between attempts, indicating the utility for studying the brain to spinal cord function underlying volitional and skilled movements in the rat.


Zalvidea, D., Castano, O., Baker, S., Castro, N., Engel, E., Trepat, X., (2019). Time-lapse intravital imaging of biomaterials integration in tissues using a multicolor multiphoton microscope Novel lasers, instruments and technology 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference , IEEE (Munich, Germany) OSA Technical Digest (Optical Society of America, 2019), paper cl_3_1

Different mechanisms are triggered when tissue is exposed to a biomaterial. The success of the biomaterial targeted process, like the release of chemicals, promoted angiogenesis, tissue regeneration, etc. depends on its integration in the tissue [1]. Studying this interaction in vivo requires the ability to image simultaneously deep immersed proteins and biomaterials with high resolution and low damage. Several methods offer solutions but only multiphoton microscopy (MM) has the ability to image with high resolution deep inside the sample. Why is not MM more extensively applied as a platform for investigating biomaterial integration in vivo? The high cost of the typical source for multiphoton microscopy is a clear limitation. Furthermore, imaging several channels simultaneously becomes out of reach for most of the labs.


López-Carral, Héctor, Santos-Pata, D., Zucca, R., Verschure, P., (2019). How you type is what you type: Keystroke dynamics correlate with affective content ACII 2019 8th International Conference on Affective Computing and Intelligent Interaction , IEEE (Cabride, UK) , 1-5

Estimating the affective state of a user during a computer task traditionally relies on either subjective reports or analysis of physiological signals, facial expressions, and other measures. These methods have known limitations, can be intrusive and may require specialized equipment. An alternative would be employing a ubiquitous device of everyday use such as a standard keyboard. Here we investigate if we can infer the emotional state of a user by analyzing their typing patterns. To test this hypothesis, we asked 400 participants to caption a set of emotionally charged images taken from a standard database with known ratings of arousal and valence. We computed different keystroke pattern dynamics, including keystroke duration (dwell time) and latency (flight time). By computing the mean value of all of these features for each image, we found a statistically significant negative correlation between dwell times and valence, and between flight times and arousal. These results highlight the potential of using keystroke dynamics to estimate the affective state of a user in a non-obtrusive way and without the need for specialized devices.

Keywords: Feature extraction, Correlation, Keyboards, Task analysis, Statistical analysis, Affective computing, Standards, Keystroke, Keyboard, Typing, Arousal, Valence, Affect


Timmers, H., Kowligy, A., Lind, A. J., Nader, N., Shaw, J., Zalvidea, D., Biegert, J., Diddams, S. A., (2019). Hyperspectral microscopy with broadband infrared frequency combs Ultrafast Applications (SF1E) 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference , IEEE (Munich, Germany) OSA Technical Digest (Optical Society of America, 2019), paper SF1E.4

We present a new modality for infrared, hyperspectral microscopy using dual-comb, electro-optic sampling of octave-spanning infrared frequency combs. We obtain hyperspectral images of SU8 test patterns on Si wafers with a spatial resolution of 12 µm.


Gumí-Audenis, B., Giannotti, M. I., (2019). Structural and mechanical characterization of supported model membranes by AFM Biomimetic Lipid Membranes: Fundamentals, Applications, and Commercialization (ed. Kök, Fatma N., Arslan Yildiz, Ahu, Inci, Fatih), Springer International Publishing (Cham, Germany) , 1-27

Several cellular processes, including adhesion, signaling and transcription, endocytosis, and membrane resealing, among others, involve conformational changes such as bending, vesiculation, and tubulation. These mechanisms generally involve membrane separation from the cytoskeleton as well as strong bending, for which the membrane chemical composition and physicochemical properties, often highly localized and dynamic, are key players. The mechanical role of the lipid membrane in force triggered (or sensing) mechanisms in cells is important, and understanding the lipid bilayers’ physical and mechanical properties is essential to comprehend their contribution to the overall membrane. Atomic force microscopy (AFM)-based experimental approaches have been to date very valuable to deepen into these aspects. As a stand-alone, high-resolution imaging technique and force transducer with the possibility to operate in aqueous environment, it defies most other surface instrumentation in ease of use, sensitivity and versatility. In this chapter, we introduce the different AFM-based methods to assess topological and nanomechanical information on model membranes, specifically to supported lipid bilayers (SLBs), including several examples ranging from pure phospholipid homogeneous bilayers to multicomponent and phase-separated SLBs, increasing the bilayer complexity, in the direction of mimicking biological membranes.

Keywords: Atomic force microscopy, Force spectroscopy, Model membranes, Nanomechanics, Supported lipid bilayers


Martinez-Hernandez, Uriel, Vouloutsi, Vasiliki, Mura, Anna, Mangan, Michael, Asada, Minoru, Prescott, T. J., Verschure, P., (2019). Biomimetic and Biohybrid Systems 8th International Conference, Living Machines 2019, Nara, Japan, July 9–12, 2019, Proceedings , Springer, Cham (Lausanne, Switzerland) 11556, 1-384

This book constitutes the proceedings of the 8th International Conference on Biomimetic and Biohybrid Systems, Living Machines 2019, held in Nara, Japan, in July 2019. The 26 full and 16 short papers presented in this volume were carefully reviewed and selected from 45 submissions. They deal with research on novel life-like technologies inspired by the scientific investigation of biological systems, biomimetics, and research that seeks to interface biological and artificial systems to create biohybrid systems.

Keywords: Artificial intelligence, Biomimetics, Computer architecture, Human robot interaction, Human-Computer Interaction (HCI), Humanoid robot, Image processing, Learning algorithms, Mobile robots, Multipurpose robots, Neural networks, Quadruped robots, Reinforcement learning, Robot learning, Robotics, Robots, Sensor, Sensors, Swarm robotics, User interfaces