We are a research group in the Mechanical Engineering Department of San Diego State University in southern California.  Our diverse team of researchers includes mechanical, chemical, and electrical engineers as well as bioengineers. Our research areas include MEMS, micro- and nano-fabrication, bionanoelectronics, microfluidics/nanofluidics, polymer-based photovoltaic technology, and computational sciences. Our group collaborates with researchers at our institution and other national MEMS programs (including the various academic and industrial groups that spun-off the core Nanogen technology). We also have an active international program involving seminars and exchange visits. Our extended class 100 cleanroom facility (MicroFab & NanoFab Facility) (1600 sq. ft.) is equipped for most lithography processes including metal depositions, dry (DRIE) and wet etching, soft lithography, as well as characterizations including 0.25 micron resolution deep UV lithography capability with Micrascan III step and scan litho system. A brand new 400 sq.ft. organic solar processing, packaging and testing facility complements our growing research in organic solar cells.

(I) NeuroMEMS Group
Together with our collaborators at UW and MIT, we are working on flexible microelectrode neural pad that can be implanted in the brain to record data and/or stimulate specific sites. The function of the microelectrode neural pad is to sense signals from the motor cortex and then relay those signals to a small integrated circuit (IC) located on the back side electrodes. The IC then wirelessly communicates with a prosthetic or robotic limb in a closed loop manner.  Our core contribution in this area is in developing a new class of sensing and stimulating electrodes based on patternable glassy carbon which is considered as the gold-standard in electrochemistry. However, its use as in-vivo use has not been investigated well yet, due to challenge of patterning it as part of micro-devices, and – more importantly – supporting it on a flexible substrate. Our research group has developed fabricating techniques for integrating these electrodes with a flexible substrate and CMOS processes. We now have such electrodes implanted in animal models (rats) at our collaborator’s Lab at University of Washington, University of Ferrara, and Istituto Italiano di Tecnologia of Genoa in Italy. Our group is on-track in establishing our electrodes as a compelling and proven neural stimulation and sensing probes of choice for broader clinical and research neural probe applications due to their compliant stiffness, corrosion-resistance, and superior signal-to-noise ratio for both electrical and electrochemical signals.

(II) BioNanoelectronics Group
This group is investigating the feasibility and long-term stability of DNA-based bionanoelectronics platform. This platform consists off DNA molecular wires and interconnects attached to carbon/graphite microelectrodes. The boarder impact of this study is in developing nanoscale modulation of electrochemistry and electric-fields that will form basis for advancing our knowledge in large-scale bio-nanoelectronics as well as electrochemistry and electrostatics at a sub-micron-scale.

 

(III) Polymer Solar Cell Group
Using a new device architecture with light-trapping features, we have developed a new generation of polymer-based solar cells and OLED. The group also uses computational photovoltaics to develop new insights and fundamental understanding of interfacial issues between photoactive layers and electrode materials. Together with our collaborators, Dr. Kee Moon and Dr. Khaled Morsi, our work in this area has resulted in a number of patents and a licensing agreement with a company in South Korea.

(IV) Microfluidics Group

We are working on innovative yet fundamental applications that bond the principles of microfabrication, fluid dynamics, and biology. Through collaboration with Sanford Burnham Medical Research Institute in San Diego, we are working on a microfluidic device that, we believe, will make significant contributions towards isolating cancer stem cells (CSCs) from a patient’s whole blood.  This allows for a tailored approach to laying the framework for patient-specific CSC therapies. Other projects include lung-on-a-chip with our collaborators at SDSU Biology Department (Forest Rohwer & Jeremy Barr) and a cell separating microfluidic device that traps cells of certain diameters based on geometrically-enhanced microchannels.

(V) Computational Group
We have very active research in (i) computational electrochemistry for micro- and nano-electrochemical systems, and (ii) computational photovoltaics to drive our experimental work in organic PV technology. Our work in electrochemistry of micro- and sub-micron systems (microarrays, DNA/Microfluidic chips) has resulted in a number of publications. Results include the first hybridization model in electronically active microarrays and models for effect of protonation of buffers in promoting DNA hybridization in a narrow pH window.