There has been rapidly growing interest in microfabricated fluidic devices (microchips) over the past decade.  The diversity of chemical and biochemical measurement techniques that have been implemented on microchips includes various electrophoretic and chromatographic separations, chemical and enzymatic reactions, noncovalent recognition interactions, sample concentration enhancement, and cellular manipulations.  In addition, the types of samples addressed by microchips has been broad in scope, e.g., small ions and molecules, single and double stranded DNA, amino acids, peptides, and proteins. These devices have low cost and small footprints while consuming miniscule quantities of reagents and can rapidly produce precise results.  All of these features suggest the possibility to perform chemical and biochemical experimentation on a massive scale at low cost on a bench top, a goal being pursued by many laboratories around the world.

We have become interested in the use of microfluidic devices for point of care clinical diagnostics.  We are developing devices that will allow enumeration of specific circulating cell phenotypes using a finger stick blood sample and approximately 30 minutes of processing time.  The device first isolates leukocytes from the blood sample and then subjects the leukocytes to immunophenotyping using an integrated flow cytometer.  In further developments, we intend to quantify specific cellular proteins in cells isolated in the flow cytometry stage of the device.  Detailed analysis of protein expression at the single cell level could have significant impact on the ability to diagnose disease states.  Furthermore, putting this capability into a low cost disposable microfluidic package would readily allow access to such information to a broad range of communities.