(5bv) Nano and Micro-Fluidic Systems for Biological and Biomedical Applications

The goal of my research is to develop new technologies that employ novel fluidic and electro-kinetic strategies tailored to the micro and nano scales. I like to focus my efforts on biological / biomedical applications such as the rapid detection of pathogens, continuous physiological monitoring, genomics and proteomics. Specific projects underway include:

1.Microfluidic Analytical Separator for Proteomics (micro-ASP): The proteome (the sum of all proteins) in serum is an important indication of the patient physiology. With support from NASA, we are working with SHOT Inc. (www.shot.com), to develop a fully integrated 2-D proteomics micro-device that performs isoelectric focusing and size exclusion chromatography in fluid filled micro-channels and uses micro-impedance sensors to measure protein concentrations. This device should offer advantages in portability and automation compared to the standard 2-D gel.

2.Microfluidic Electrokinetic Prefractionator for Biomolecules (micro-E-sep): Biomarker(s) of clinical interest are often present at very low concentrations (~ ng/ml) and high abundance (but non-clinically significant) proteins need to be removed prior to analysis by 2D gel or other methods. We are developing a multi-modular microfluidic device that accepts a sample of clinical interest such as serum, and, in a short period of time (1- 6 hours) pre-fractionates it and yields sub-sample(s) that are stripped of the commonly occurring high abundance proteins AND have a greatly increased (10^3-10^4 fold) concentration of clinically significant proteins of interest. The microfluidic platform utilizes ?digitized? micro-drops generated using converging immiscible flows and micro-electrodes to effect electro-kinetic transport of proteins.

3.Rapid Detection of antibiotic susceptibility of pathogenic micro-organisms: We have developed a multi-frequency reactance measurement technique that can exploit the electric field concentration within a micro-channel and the sensitivity of the bulk solution capacitance to the bacteria population to detect low concentrations (~100 CFU/ml) of bacteria in solution, and monitor their growth using. The Antibiotic susceptibility profile for a strain of E. coli has been determined in less than seven hours (compared to 2-5 days for current standards).

4.Continuous Blood glucose monitoring for ICU patients: Critically ill patients may need to have their blood glucose monitored ?continuously? (once every five minutes). We have designed a microfluidic system to do so that includes a continuous micro-filtration unit that extracts cell free plasma from blood supply. In situ electro-kinetic micro-mixers ensure the prolonged operation of the device by minimizing filter cake build-up.

In addition, an area of research that I propose to explore in the future is the utilization of the unique properties of nano-structures (such as the large induced dipoles of nanowires and nanotubes and ?hindered diffusion? in nano-porous membranes) to further enhance our ability to isolate and/or detect biomarkers and particles of interest.