Microfabricated Intrachannel Electrical Contacts for Material Transport Control

Abstract

Interest in microfabricated fluidic channel structures (microchips) has grown tremendously over the past decade due to the large number of powerful demonstrations that have appeared in the literature. The diversity of chemical and biochemical measurement techniques implemented on microchips is large including 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. The most popular method for inducing material transport through microchip channels has been by electrokinetic means, i.e., electrophoretic transport of ions and electroosmotic bulk fluid flow. Electrokinetic transport, although not the panacea, has proven quite effective for simple devices and has the convenience of only requiring simple electrical connections between a device controller and the microchip.