Targeted therapeutics and nanodevices


Silvia Muro | Group Leader / ICREA Research Professor
Belén García Lareu | Postdoctoral Researcher
Marcelle Silva de Abreu | Postdoctoral Researcher
Josep Fumadó Navarro | PhD Student
Jan Hasa | PhD Student
Maximilian Loeck | PhD Student
Marco Vigo | PhD Student


Our research sits at the interface between molecular-cellular biology and nanotechnology-drug delivery. We study the biological mechanisms ruling how our cells and tissues transport cargoes to precise destinations within our bodies, and apply this knowledge to the design of “biologically-controlled” nanodevices for improved delivery of therapeutic agents to specific disease sites (Figure 1) 

Figure 1. Targeted drug carriers for specific access within the body and its cells. Pictures are reproduced or adapted from the following sources (Copyrights reside on the respective publishers and associated professional societies): [1] Mane et al. (2012) Int J Nanomedicine, 7:4223-4237; [2] Garnacho et al. (2008) J Pharm Exp Ther, 325(2):400-408; [3] Finikova et al. (2008) Chem Phys Chem, 9(12):1673-1679; [4] Hsu et al. (2013) J Biomed Nanotech. 10(2):345-354; [5] Rosin et al. (2008) J Nucl Med, 49(1):103-111; [6] Ghaffarian et al. (2012) J Control Release, 163(1):25-33; [7] Serrano et al. (2012) Arterioscler Thromb Vasc Biol, 32(5):1178-1185; [8] Muro S. (2014) Adv Funct Mat, 24(19):2899-2906.

A plethora of promising tools are becoming available to tackle health problems, such as new drug carriers or delivery systemsmacromolecular assemblies within the nanoscale-size range which can be loaded with diagnostic and therapeutic agents to improve their solubility, dosage, circulation, biodistribution and, hence, overall performance and safety. However, despite such great advance and promise, our ability to treat diseases such as neurological maladies, genetic syndromes, cancer, etc., remains a major challenge. One of the prime obstacles is our limited knowledge on the biological parameters that regulate the interaction of these systems with our tissues and, hence, our inability to gain non-invasive, efficient, and specific access within the body, its cells, and subcellular organelles. Our lab generates knowledge and tools aimed to improve our ability to deliver therapeutic agents to specific disease sites. Focusing on endothelial cell adhesion molecules as examples of accessible targets and on genetic conditions which serve as models for metabolic, neurodegenerative and cardiovascular syndromes, our ultimate goal is to enable effective treatment for these life-threatening disorders and other maladies characterized by similar pathological traits. Some of our main programmatic efforts are described below. 


Biologically-Controlled Transport of Drug Carriers

How drug delivery systems are sensed, transported, and disposed of within the body, which is greatly dependent upon biological properties and processes, is far from being understood and much less controlled. Most targeted strategies are designed to achieve specific binding of drug delivery systems to cell-surface receptors, but then they simply depend on the signaling and transport processes the bound receptor regulates in nature. Instead, by deciphering the biological bases of these events, we impart the drug carrier control over biological signaling events independently from the receptor being bound, bypassing the mechanisms, kinetics, and destinations otherwise associated with these receptors. This provides a new and complementary avenue at the interface between the use of novel technological tools to decipher the biological mechanisms that regulate health and fail in disease, and the use of biological knowledge to optimize nanotechnology tools aimed to diagnose and treat human pathologies. For instance, we have shown how even using the same targeting or receptor, the kinetics, mechanism, and destination of a drug carrier can be modulated by: (a) varying its size, shape, and targeting valency; (b) varying the receptor epitope to which the carrier binds; (c) using auxiliary drugs to modulate the endocytic machinery; (d) coupling carriers to signaling molecules that can tune the uptake route independently from the receptor being used (Figure 2); (e) combining targeting to several receptors; or (f) coupling targeting moieties with anti-phagocytic moieties on the surface of drug carriers 

Figure 2. Enzyme-functionalization of drug carriers to improve their uptake by cells. ICAM-1-targeted nano- and micro-carriers are both internalized by cells due to natural sphingomyelinase (SMase)-dependent generation of ceramide at ICAM-1-binding sites. Ceramide improves carrier engulfment and membrane invagination, and acts as a second messenger toward actin re-organization, helping endocytic uptake (left panel). In contrast, targeting drug carriers to receptors associated with more size-restrictive pathways, e.g., clathrin-associated mannose-6-phosphate receptor (M6PR), often enables uptake of nano- but not micro-carriers (middle panel). Surface-functionalization of M6PR-targeted carriers with elements mimicking the ICAM-1 pathway, namely exogenous SMases (such as NSM), supplies the necessary ceramide and actin re-organization, improving endocytosis of nano- and micro-carriers even when targeted to receptors different from ICAM-1 (right panel). Reproduced from Ansar et al. (2013) ACS Nano, 7(12):10597-10611.

Examples of these strategies can be found in: 

Muro et al. (2008) Controlled endothelial targeting and intracellular delivery of therapeutics by modulating size and shape of ICAM-1-targeted carriers. Mol Ther16(8):1450-1458.  

Garnacho et al. (2008) Differential intra-endothelial delivery of polymer nanocarriers targeted to distinct PECAM-1 epitopesJ Control Rel, 130(3):226-233.   

-Ansar et al. (2013) Biological functionalization of drug delivery carriers to bypass size restrictions of receptor-mediated endocytosis independently from receptor targeting. ACS Nano. 7(12):10597-10611. 

-Papademetriou et al. (2013) In vivo performance of polymer nanocarriers dually-targeted to epitopes of the same or different receptors. Biomaterials. 34(13):3459-3466. 

Papademetriou et al. (2014) Combination-targeting to multiple endothelial cell adhesion molecules modulates binding, endocytosis, and in vivo biodistribution of drug nanocarriers and their therapeutic cargoes. J Control Release, 188:87-98. 

Serrano et al. (2016) How carrier size and valency modulate receptor-mediated signaling: understanding the link between binding and endocytosis of ICAM-1-targeted carriers. Biomacromolecules. 17(10):3127-3137. 

-Kim et al. (2017) Co-coating of receptor-targeted drug nanocarriers with anti-phagocytic moieties enhances specific tissue uptake versus non-specific phagocytic clearance. Biomaterials, 147:14-25.  


Transport of Drug Carriers Across Physiological Barriers

 Crossing the linings that separate body and cellular compartments is paramount for efficient drug delivery. For instance, an epithelial barrier separates the gastrointestinal tract from the bloodstream, controlling uptake of orally ingested substances. While certain chemical entities are able to cross this barrier, many therapies do not and their successful utilization needs of means to bypass this obstacle. As for neurodegenerative conditions, they remain largely untreatable because the vast majority of available pharmaceuticals and drug carriers under development both fail to traverse the endothelial barrier that separates the bloodstream from the brain tissue. Another example is that of novel biological therapeutics, which have demonstrated potential to manipulate disease targets far more precisely than their small chemical counterparts. However, these large and fragile therapeutics fail to traverse the membranes that separate the extracellular environment from the intracellular milieu and those of intracellular organelles. We demonstrated that the ICAM-1 pathway (described in the next section) enables transcytosis across epithelial and endothelial linings, which we explore for oral delivery and delivery across the blood-brain barrier. We were also able to target DNA-built dendrimers to cells specifically, whereby these DNA dendrimers enabled endosomal escape and cytosol delivery of a variety of cargoes, including small toxins, carbohydrates (Figure 3), proteins, and nucleic acids.  

Figure 3. Subcellular distribution of cargo delivered by targeted DNA-built dendrimers. (Left) Illustrative cartoon and corresponding microscopy showing that fluorescent dextran delivered to cells via targeted polymer nanoparticles resides in vesicular compartments (bright red spots) around the cell nucleus (blue). (Right) Instead, much dextran can escape vesicular compartments and reach the cytosol (more diffuse red color) when delivered using similarly targeted “nucleodendrimers” (DNA-built dendrimers). Adapted from Muro (2014) Adv Funct Mat, 24(19):2899-2906.

Examples of these strategies can be found in: 

Ghaffarian et al. (2012) Transport of nanocarriers across gastrointestinal epithelial cells by a new transcellular route induced by targeting ICAM-1. J Control Release, 163(1):25-33.  

-Hsu et al. (2014) Specific binding, uptake, and transport of ICAM-1-targeted nanocarriers across endothelial and subendothelial cell components of the blood-brain barrier. Pharm Res. 31(7):1855-1866. 

Muro. (2014) A DNA device that mediates selective endosomal escape and intracellular delivery of drugs and biological. Adv Funct Mat, 24(19):2899-2906. 

-Hsu et al. (2015) Targeting, endocytosis and lysosomal delivery of active enzymes to the cell body and processes of model human neurons by ICAM-1-tageted nanocarriers. Pharm Res. 32(4):1264-1278.  

Ghaffarian et al. (2016) Chitosan-alginate microcapsules provide gastric protection and intestinal release of ICAM-1-targeting nanocarriers, enabling GI targeting in vivo. Adv. Func. Mat. 26(20):3382-3393.    


Vesicular Transport of Endothelial Cell Adhesion Molecules

During my postdoctoral training, I helped to identify an endocytic pathway induced upon multivalent engagement of the endothelial cell-surface molecules ICAM-1 and PECAM-1This new transport route is different from most others classically utilized for drug delivery, including clathrin-, caveolar-, macropinocytosis-, or phagocytosis-mediated pathways. My independent laboratory continues to unravel the regulation of this route, particularly focusing on ICAM-1 (Figure 4), and its implications in patho-physiology and drug delivery. The relevance of this new pathway is illustrated by the fact that ICAM-1 mediates extravasation of leukocytes during inflammation, signaling at the immune synapsis, and invasion by some pathogens (e.g., human rhinoviruses). The understanding of this fundamental route and its properties is also advancing diverse drug delivery applications by our group and many others 

Figure 4. Cell adhesion molecule (CAM)-mediated endocytosis. (Top) Different magnifications of microscopy images showing precise co-localization of sodium-proton exchanger 1 (NHE-1; red) and acid sphingomyelinase enzyme (ASM; green) at plasmalemma areas where ICAM-1-targeted carriers are being engulfed by cells. (Bottom) Relative enrichment of ceramide in regions of binding of ICAM-1-targeted carriers to control cell versus cell treated with EIPA (an NHE-1 inhibitor) shows that NHE-1 function is needed for membrane engulfment of said carriers. Adapted from Serrano et al. (2012) Arterioscler Thromb Vasc Biol, 32(5):1178-1185.

Examples of these studies can be found in: 

-Muro et al. (2003) A novel endocytic pathway induced by clustering endothelial ICAM-1 or PECAM-1. J Cell Sci, 116(8): 1599-1609.  

Serrano et al. (2012) Intercellular adhesion molecule 1 engagement modulates sphingomyelinase and ceramide, supporting uptake of drug carriers by the vascular endothelium. Arterioscler Thromb Vasc Biol32(5):1178-1185.  

Ghaffarian et al. (2014) Distinct subcellular trafficking resulting from monomeric vs. multimeric targeting to endothelial ICAM-1: implications for drug delivery. Mol Pharm. 11(12):4350-4362. 

-Manthe et al. (2017) ICAM-1-targeted nanocarriers attenuate endothelial release of sICAM-1, and inflammatory regulator. Bioeng. Transl. Med. 2(1): 109-119. 


Improving Treatment of Lysosomal Disorders

Monogenic pathologies due to genetic deficiency, such as the case of lysosomal disorders, are valuable models to study disease progression and therapeutic intervention because they have well-known etiology and defined molecular, biochemical and cellular effects, and because patient samples, diverse cell types, and small and large animal models are all readily available. Also, their unequivocal diagnosis enables the tracing of their progression from early to late stages. Since these diseases present with either acute or long-term effects depending on genetic severity, and associate with neurodegeneration, cardiovascular, metabolic, and cancer-like syndromes, they represent excellent disease models. The current lack of efficient therapies to treat these syndromes stems from problems similar to those described above, i.e. our inability to deliver therapeutics to disease sites in need. Consequently, we are applying targeted nanotechnology concepts to the treatment of genetic lysosomal disorders. Current therapies by i.v. enzyme infusion are only helpful for diseases where clearance cells and organs (liver, spleen, macrophages, etc.) are the main targets. Yet, delivery to other organs (brain, lungs, etc.) hinders translation for most diseases. Using types A and B Niemann-Pick (Figure 5), Fabry, and Gaucher diseases as examples, we have shown improved delivery of therapeutic enzymes to all affected organs in animal models, holding considerable translational potential. 

Figure 5. Endocytosis and lysosomal trafficking of anti-ICAM/ASM NCs in mouse lungs. (Top) Polymer nanocarriers (NCs) bearing therapeutic acid sphingomyelinase (ASM) and targeted to ICAM-1 were observed by fluorescent microscopy to abundantly reach the lungs, as observed 30 min after i.v. injection in mice (green spots). (Bottom) Transmission electron microscopy of lungs collected 3 h after i.v. administration confirmed the presence of NCs (green) interacting with endothelial cells (ECs). For instance, NCs can be seen being engulfed by cells (black arrows), within cell endosomes (white arrowheads) and lysosomes (black arrowheads), and transcytosed across the endothelium into subjacent epithelial cells (white arrow). VL = vessel lumen. Cv = caveolar vesicles. Cl = clathrin vesicles. Cj = cell junction. Scale bars = 300 nm. Reproduced from Garnacho et al. (2017) Mol. Ther. doi: 10.1016/j.ymthe.2017.05.014.

Examples of these studies can be found in: 

– Garnacho et al. (2008) Delivery of acid sphingomyelinase in normal and Niemann-Pick disease mice using ICAM-1-targeted polymer nanocarriers. J Pharm Exp Ther, 325(2):400-408.  

– Hsu et al. (2011) Enhanced endothelial delivery and biochemical effects of α-galactosidase by ICAM-1-targeted nanocarriers for Fabry disease. J Control Rel, 10;149(3):323-331.  

– Hsu et al. (2012) Enhanced delivery of [Símbolo]-glucosidase for Pompe disease by ICAM-1-targeted polymer nanocarriers comparative performance of a strategy for three distinct lysosomal storage disorders. Nanomed, 8(5):731-739.  

– Hsu et al. (2014) Enhancing the biodistribution of therapeutic enzymes in vivo by modulating surface coating and concentration of ICAM-1-targeted nanocarriers. J Biomed Nanotech, 10(2):345-354. 

– Rappaport et al. (2016) A Comparative study on the alterations of endocytic pathways in multiple lysosomal storage disorders. Mol Pharm13(2):357–368. 

– Garnacho et al. (2017) Endothelial delivery and effects of acid sphingomyelinase by ICAM-1 targeted nanocarriers in type B Niemann-Pick disease. Mol. Therdoi: 10.1016/j.ymthe.2017.05.014. 



National projects
CROSSTARGET · Desarrollo de nuevas herramientas traslacionales multi-especie para el direccionamiento de terapias con precisión de órgano y subcelular (2019 – 2021) Ministerio de Ciencia, Innovación y Universidades Silvia Muro
BBB2GATE · Control diferencial del transporte de vehiculos terapeuticos dentro versus a traves de la barrera hematoencefalica (2018 – 2020) MINECO Silvia Muro
NANO-GBA · Assessing the effects of glucocerebrosidase (GBA) alterations on receptor membrane nanoarchitecture to design improved nanomedicines(2020 – 2021) BIST Ignite Program Silvia Muro
Fundraising Projects
Campaña FasterFuture “A por el Parkinson”  (2019 – 2020) Fundraising Silvia Muro


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

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.

Muro, Silvia, (2018). Alterations in cellular processes involving vesicular trafficking and implications in drug delivery Biomimetics 3, (3), 19

Endocytosis and vesicular trafficking are cellular processes that regulate numerous functions required to sustain life. From a translational perspective, they offer avenues to improve the access of therapeutic drugs across cellular barriers that separate body compartments and into diseased cells. However, the fact that many factors have the potential to alter these routes, impacting our ability to effectively exploit them, is often overlooked. Altered vesicular transport may arise from the molecular defects underlying the pathological syndrome which we aim to treat, the activity of the drugs being used, or side effects derived from the drug carriers employed. In addition, most cellular models currently available do not properly reflect key physiological parameters of the biological environment in the body, hindering translational progress. This article offers a critical overview of these topics, discussing current achievements, limitations and future perspectives on the use of vesicular transport for drug delivery applications.

Keywords: Cellular vesicles, Vesicle fusion, Fission and intracellular trafficking, Drug delivery systems and nanomedicines, Transcytosis and endocytosis of drugs carriers, Disease effects on vesicular trafficking, Drug effects on vesicular trafficking, Role of the biological environment



  • Dr. Alexander Andrianov, University of Maryland, MD, USA.
  • Dr. Yu Chen, University of Maryland College Park, MD, USA.
  • Dr. Mandy Esch, National Institutes for Standards and Technology, Gaithersburg, MD, USA.
  • Dr. Robert Getts, Genisphere LLC, Hatfield, PA, USA.
  • Dr. Hamid Ghandehari, University of Utah, UT, USA.
  • Dr. Janet Hoenicka, Sant Joan de Deu Hospital, Barcelona, Spain.
  • Dr. Christopher Jewell, University of Maryland College Park, MD, USA.
  • Dr. Joe Kao, University of Maryland Baltimore, MD, USA.
  • Dr. Peter Kofinas, University of Maryland College Park, MD, USA.
  • Dr. Juan Marugan and Dr. Wei Zheng, National Institutes of Health, Rockville, MD, USA.
  • Dr. Vladimir Muzykantov, University of Pennsylvania, Philadelphia, PA, USA.
  • Dr. Gianfranco Pasut, University of Padova, Padova, Italy.
  • Dr. Edward Schuchman, Mount Sinai School of Medicine, New York, NY, USA.
  • Dr. Brigitte Stadler, Aarhus University, Denmark.
  • Dr. Maria Jesus Vicent, Principe Felipe Research Center, Valencia, Spain.





IBEC researchers find a new way to effectively transport drugs to the brain

An international group of researchers from the University of Maryland (United States) and the Institute for Bioengineering of Catalonia (IBEC) led by ICREA Research Professor Silvia Muro, has identified a new way of transporting drugs to the brain, one of the major challenges of the pharmaceutical science today, that could help to come up with new treatments for neurological diseases such as Parkinson’s or Alzheimer’s.

To find this out, the experts linked an antibody capable of recognizing the ICAM-1 protein -a molecule expressed on the surface of blood vessels- to a series of polymeric nanoparticles that can transport drugs and inject them intravenously.

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The second edition of IBEC’s Faster Future programme will be dedicated to the fight against Parkinson

The programme IBEC Faster Future, an initiative that aims to help accelerate research projects that are close to tackling major challenges in health, will enable the development of a new antibody that will be the base of a therapeutic product for the treatment of Parkinson’s disease.

The Faster Future program campaign “Let’s tackle Parkinson”, which is launched today and will remain open to donations until the 30th of April, has the aim to raise 50,000 € needed to accelerate this research, seeking to obtain favourable results within a year and a half.

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IBEC project to defy blood-brain barrier awarded in highly competitive call

IBEC group leader Silvia Muro has been granted funding in MINECO’s ‘Explora Ciencia’ and ‘Explora Tecnología’ 2017 call.

It’s the first competitive grant for Silvia and her group since she joined IBEC at the end of 2017, and one of only 97 research projects to be financed out of the 1594 applications submitted – a success rate of only 6%.

The project, ‘Controlling the differential transport of therapeutic cargoes into versus across the BBB (BBB2GATE)’ will aim to develop drug vehicles that can cross the blood-brain barrier using the natural routes that the body’s substances use to circumvent this obstruction.

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