Staff member

Raquel Obregón Núñez

Senior Technician
Biomimetic Systems for Cell Engineering
+34 934 020 543
Staff member publications

De Goede, M., Chang, L., Dijkstra, M., Obregón, R., Ramón-Azcon, J., Martínez, E., Padilla, L., Adan, J., Mitjans, F., García-Blanco, S.M., (2018). Al2O3 Microresonator based passive and active biosensors ICTON 2018 20th International Conference on Transparent Optical Networks , IEEE Computer Society (Bucharest, Romania) , 8473820

Al2O3 microresonators were realized for sensing applications of both passive and active devices. Passive microring resonators exhibited quality factors up to 3.2×105 in air. A bulk refractive index sensitivity of 100 nm/RIU was demonstrated together with a limit of detection of 10-6 RIU. Functionalizing their surface allowed for the label-free detection of the biomarker rhS100A4 from urine with a limit of detection of 3 nM. Furthermore, single-mode Al2O3:Yb3+ microdisk lasers were realized that could operate in an aqueous environment. Upon varying the bulk refractive index their lasing wavelength could be tuned with a sensitivity of 20 nm/RIU and a LOD of 3×10-6 RIU.

De Goede, M., Chang, L., Dijkstra, M., Obregón, R., Ramón-Azcon, J., Martínez, E., Padilla, L., Adan, J., Mitjans, F., García-Blanco, S.M., (2018). Al2O3 Mmicroresonators for passive and active sensing applications Sensors 2018 Optical Sensors , OSA - The Optical Society (Zurich, Switzerland) Part F110, 1-2

The Al2O3 waveguide technology was explored for sensing applications. Passive microring resonators with a quality factor in air of 3.2×105 were developed with a bulk refractive index sensitivity of ~100 nm/RIU and limit of detection of ~10-6 RIU. These were functionalized to detect the biomarker rhS100A4 from urine down to concentrations of 3 nM. Furthermore, Al2O3:Yb3+ microdisk lasers were realized that exhibited single mode lasing operation in water. Their lasing wavelength was tuned by varying the bulk refractive index and a bulk refractive index sensitivity of ~20 nm/RIU with a LOD of ~3×10-6 was achieved.

de Goede, M., Dijkstra, M., Obregón, R., Martínez, E., García-Blanco, S.M., (2018). High quality factor Al2O3 microring resonators for on-chip sensing applications Proceedings SPIE. Integrated Optics: Devices, Materials, and Technologies XXII SPIE OPTO , SPIE (California, USA) 10535, 7

Microring resonators find many applications for on-chip integrated optical sensors. Their spectral response contains resonance dips that shift due to variations of the optical path length of the microring probed. Numerous examples of such microring resonator sensors in the SOI, Si3N4 and SiON waveguide technologies have been reported for the detection of bulk refractive index variations and the label-free detection of biomarkers. Al2O3 is an alternative waveguide technology that exhibits low optical propagation losses, is transparent over a large spectral range extending from the visible to the mid-IR and permits co-doping with active rare-earth ions, which enables the co-integration of active devices on the chip. In this work an Al2O3 microring resonator sensor was developed for the label-free detection of protein biomarkers. The uncladded microring with a radius of 200 μm had a measured quality factor of 3.2 × 105 at 1550 nm. Submerging the devices in water decreased the quality factor to 45 × 103. This corresponds with propagation losses in the rings of 0.6 dB/cm and 5.7 dB/cm respectively. The bulk refractive index sensitivity of the sensor was determined by flowing NaCl dissolved in water in different concentrations. A sensitivity of 102.3 ± 0.5 nm/RIU with a corresponding limit of detection of 1.6 × 10-6 RIU was demonstrated for TM polarized light. High affinity human monoclonal antibodies mAb S100A4 were immobilized on the sensor to detect the S100A4 protein biomarker down to 12 nM concentrations. These results demonstrate the feasibility of this material for label-free optical biosensors.

Mohammadi, M. H., Obregón, R., Ahadian, S., Ramón-Azcón, J., Radisic, M., (2017). Engineered muscle tissues for disease modeling and drug screening applications Current Pharmaceutical Design 23, (20), 2991-3004

Animal models have been the main resources for drug discovery and prediction of drugs’ pharmacokinetic responses in the body. However, noticeable drawbacks associated with animal models include high cost, low reproducibility, low physiological similarity to humans, and ethical problems. Engineered tissue models have recently emerged as an alternative or substitute for animal models in drug discovery and testing and disease modeling. In this review, we focus on skeletal muscle and cardiac muscle tissues by first describing their characterization and physiology. Major fabrication technologies (i.e., electrospinning, bioprinting, dielectrophoresis, textile technology, and microfluidics) to make functional muscle tissues are then described. Finally, currently used muscle tissue models in drug screening are reviewed and discussed.

Keywords: Cardiac muscle, Drug screening, Engineering muscle, Human pharmacological response, Physiological similarity, Skeletal muscle

Obregón, R., Ramón-Azcón, J., Ahadian, S., (2017). Nanofiber composites in blood vessel tissue engineering Nanofiber Composites for Biomedical Applications (ed. Ramalingam, M., Ramakrishna, S.), Elsevier (Duxford, UK) Woodhead Publishing Series in Biomaterials, 483-506

Tissue engineering (TE) aims to restore function or replace damaged tissue through biological principles and engineering. Nanofibers are attractive substrates for tissue regeneration applications because they structurally mimic the native extracellular matrix. Composite nanofibers, which are hybrid nanofibers blended from natural and synthetic polymers, represent a major advancement in TE and regenerative medicine, since they take advantage of the physical properties of the synthetic polymer and the bioactivity of the natural polymer while minimizing the disadvantages of both. Although various nanofibrous matrices have been applied to almost all the areas of TE, in this chapter we will focus on nanofiber composites scaffolds for vascular TE.

Keywords: Blood vessels, Nanofiber composite, Tissue engineering, Vascularized tissue