Papers by Raquel Perez-Castillejos
2015 41st Annual Northeast Biomedical Engineering Conference (NEBEC), 2015
2015 41st Annual Northeast Biomedical Engineering Conference (NEBEC), 2015
2015 ASEE Annual Conference and Exposition Proceedings, 2015
Nanotechnology is expected to create millions of new jobs and generate ~ $1 trillion in product r... more Nanotechnology is expected to create millions of new jobs and generate ~ $1 trillion in product revenues worldwide by 2015.1,2 Research and development in nanotechnology is likely to change completely the design, analysis, and manufacturing for a wide range of engineering products. Nanotechnology, however, is still mostly a topic for graduate schools whereas undergraduate programs that focus on nanotechnology remain sporadic.3 Our NSF-NUE award will build a multidisciplinary, cross-campus educational program that integrates nanotechnology to the undergraduate curricula in science and engineering. Our educational program in nanotechnology will also reach out to high school (K9-K12) and graduate students.
As described by the National Science Foundation (NSF), REU sites are summer programs that offer R... more As described by the National Science Foundation (NSF), REU sites are summer programs that offer Research Experiences to Undergraduates with the goal of “engag[ing] a number of students in research.” In NSF-funded REU programs, about ten students from different parts in the country meet at the REU hosting institution and perform research and career-development activities for 10 weeks. The NSF-funded REU program at our Institute is the first one that focuses on Neural Engineering: a hot topic in research and also highly sought after by students. Neural engineering is a rapidly growing interdisciplinary research area that takes an engineering approach to analyze neurological function and to understand, repair, replace, or enhance the nervous system. The main goal of a neural engineer is to develop solutions to neurological and rehabilitative problems. The REU site in neural engineering (NEURON REU) at the New Jersey Institute of Technology (NJIT) is led by our biomedical engineering de...
2013 39th Annual Northeast Bioengineering Conference, 2013
ABSTRACT We introduce here an approach for determining the exposure time in photolithography. A s... more ABSTRACT We introduce here an approach for determining the exposure time in photolithography. A script was developed in LabVIEW that (i) measures (via UV sensor) the intensity (or power) of UV light to which a sample is exposed at different times, (ii) calculates the total energy delivered onto the sample, and (iii) switches off the UV lamp as soon as the sample (a photocurable material) has received the targeted total energy of UV light. In comparison to standard approaches to photolithography in which the lamp is switched off after a given amount of time pre-selected by the user, our approach determines experimentally the energy received by the sample and switches the UV lamp off when the sample has received the intended UV energy -- independently of how long it took for the lamp to produce that amount of energy.
2013 39th Annual Northeast Bioengineering Conference, 2013
ABSTRACT Metallic mirrors are important components of optomicrofluidic systems for their good ref... more ABSTRACT Metallic mirrors are important components of optomicrofluidic systems for their good reflection properties. Their use, however, has remained challenging due to their difficult integration. We describe the integration of Indium (In) mirrors into microfluidic devices for optical detection using an approach that is fast, simple, and inexpensive.
Chemical Physics Letters, 2010
We used surface-enhanced Raman spectroscopy (SERS) to detect binding events between streptavidin ... more We used surface-enhanced Raman spectroscopy (SERS) to detect binding events between streptavidin and biotinylated lipid bilayers. The binding events took place at the surface between micro-fluidic channels and anodized aluminum oxide (AAO) with the latter serving as substrates. The bilayers were incorporated in the substrate pores. It was revealed that non-bound molecules were easily washed away and that large suspended
International Symposium on Electronic Commerce, 2012
The Department of Biomedical Engineering at the New Jersey Institute of Technology (NJIT) develop... more The Department of Biomedical Engineering at the New Jersey Institute of Technology (NJIT) developed a BioMEMS Summer Bioengineering Institute. The focus on BioMEMS was supported by both didactic and research activities planned for the students. The research experience consisted on (i) designing and (Ii) fabricating a BioMEMS device in the Class-10 Cleanroom of the Microelectronics Facility at the New Jersey
2007 International Conference on Thermal, Mechanical and Multi-Physics Simulation Experiments in Microelectronics and Micro-Systems. EuroSime 2007, 2007
Abstract A magnetic microfluidic valve has been analyzed to improve its performance. Operation re... more Abstract A magnetic microfluidic valve has been analyzed to improve its performance. Operation relies on the use of a permanent magnet which interacts with an electrodeposited layer of Co-Ni on a V-shaped cantilever beam. The deflection caused by the magnetic forces opens or closes the fluid flow. The microvalve performance has been optimized by means of finite element analysis. The FEA model has been experimentally validated using confocal microscopy and used to improve the magnetic circuit. Then, a fluidic cell has been built ...
IEEE 2nd Integrated STEM Education Conference, 2012
Abstract The Department of Biomedical Engineering at the New Jersey Institute of Technology (NJIT... more Abstract The Department of Biomedical Engineering at the New Jersey Institute of Technology (NJIT) developed a BioMEMS Summer Bioengineering Institute. The focus on BioMEMS was supported by both didactic and research activities planned for the students. The research experience consisted on (i) designing and (Ii) fabricating a BioMEMS device in the Class-10 Cleanroom of the Microelectronics Facility at the New Jersey Institute of Technology, and finally (iii) testing their device in a host biomedical research lab either in ...
Transducers ’01 Eurosensors XV, 2001
Integr. Biol., 2015
In retinal degeneration, death of photoreceptors causes blindness. Repair of the retina by transp... more In retinal degeneration, death of photoreceptors causes blindness. Repair of the retina by transplanting photoreceptors has resulted in limited functional connectivity between transplanted and host neurons. We hypothesize that absence of appropriate biological cues, specifically positional (retinotopographic) cues, reduces synaptogenesis. Here we use micropatterning to test whether regional origin affects the early synaptic development of photoreceptors. Right and left retinas from salamanders were first labelled with dextran tetramethyl-rhodamine and fluorescein, respectively, bisected into nasal (N)/temporal (T) or dorsal (D)/ventral (V) halves, individually dissociated, mixed, and cultured for 1 week. Origin of cells was identified by the fluorescent label. Interactions between photoreceptors and neighboring (target) cells were assessed by the number of neuritic contacts with a presynaptic swelling (varicosity). Randomly-plated photoreceptors showed no preference for cellular origin, likely due to multiple potential interactions available to each cell. To reduce cell-cell interactions, culture substrate was patterned using a microfluidic device with 10 μm-wide channels separated by 200 μm, thus allowing only 1-2 targets per photoreceptor. In patterned cultures, 36.89% of N rod cells contacted T targets but only 27.42% of N rod cells contacted N targets; similarly 35.05% of T rod cells contacted N cells but only 17.08% contacted T cells. Thus, opposite regions were more permissive of contact. However, neither cone nor D/V rod cells showed preferences for positional origin of targets. In conclusion, micropatterning demonstrated that neuritic differentiation by rod cells depends on retinotopographic cues along the nasal/temporal plane, suggesting that transplanting rod cells of known positional origin will increase transplant success.
Sensors and Actuators a-Physical, 2010
Design, fabrication and testing of a novel micromachined “quasi-digital” microflow regulator for ... more Design, fabrication and testing of a novel micromachined “quasi-digital” microflow regulator for integrated microfluidic systems. Operation relies on the use of a permanent magnet which interacts with an electrodeposited layer of Co–Ni on an array of V-shaped cantilever beams under a constant pressure. Each valve actuates as an on–off fluidic switch, opening or closing its corresponding microchannel. The flow can be adjusted to a set of different values (digital) by changing the position of the magnet. The microflow regulator has been ...
Materials Today, 2010
The microenvironment of a cell comprises all the cues (stimuli) affecting the cell and includes a... more The microenvironment of a cell comprises all the cues (stimuli) affecting the cell and includes attachment to neighboring cells, attachment to the structural molecules of the extracellular matrix (e.g., via integrins 5-7 ), molecules secreted by the cell itself or by other cells, nutrients, oxygen, mechanical stimuli (such as shear stress), UV light, and many others. In replicas of biological tissues, cells and microenvironmental cues are (i) integrated and (ii) organized according to the in vivo 3D histoarchitecture. These replicas of living tissues would behave similarly to the original tissues and could be used in therapeutic applications (regenerative medicine) and as realistic human models of tissues for the study of cell biology and for cell-based assays.
Journal of Molecular Biology, 2013
Ca²⁺-triggered neurotransmitter release depends on the formation of SNARE complexes that bring th... more Ca²⁺-triggered neurotransmitter release depends on the formation of SNARE complexes that bring the synaptic vesicle and plasma membranes together, on the Ca²⁺ sensor synaptotagmin-1 and on complexins, which play active and inhibitory roles. Release of the complexin inhibitory activity by binding of synaptotagmin-1 to the SNARE complex, causing complexin displacement, was proposed to trigger exocytosis. However, the validity of this model was questioned based on the observation of simultaneous binding of complexin-I and a fragment containing the synaptotagmin-1 C2 domains (C2AB) to membrane-anchored SNARE complex. Using diverse biophysical techniques, here we show that C2AB and complexin-I do not bind to each other but can indeed bind simultaneously to the SNARE complex in solution. Hence, the SNARE complex contains separate binding sites for both proteins. However, total internal reflection fluorescence microscopy experiments show that C2AB can displace a complexin-I fragment containing its central SNARE-binding helix and an inhibitory helix (Cpx26-83) from membrane-anchored SNARE complex under equilibrium conditions. Interestingly, full-length complexin-I binds more tightly to membrane-anchored SNARE complex than Cpx26-83, and it is not displaced by C2AB. These results show that interactions of N- and/or C-terminal sequences of complexin-I with the SNARE complex and/or phospholipids increase the affinity of complexin-I for the SNARE complex, hindering dissociation induced by C2AB. We propose a model whereby binding of synaptotagmin-1 to the SNARE complex directly or indirectly causes a rearrangement of the complexin-I inhibitory helix without inducing complexin-I dissociation, thus relieving the inhibitory activity and enabling cooperation between synaptotagmin-1 and complexin-I in triggering release.
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Papers by Raquel Perez-Castillejos