ELECTROOSMOTIC PUMPING AND VALVELESS CONTROL OF FLUID-FLOW WITHIN A MANIFOLD OF CAPILLARIES ON A GLASS CHIP

Fluid flow was driven within a network of intersecting capillaries int egrated on a glass chip using electroosmotic pumping. Potentials could be applied to several capillaries simultaneously to quantitatively co ntrol the amount of each reagent stream delivered to an intersection o f capillaries. An example of a simple dilution of sample with buffer i s shown. Kirchhoffs rules for resistive networks were found to predict the currents and fluid flow within the capillaries. Leakage of sample from one channel to another at an intersection was shown to arise fro m both diffusive and hydrodynamic effects. Application of potentials t o the intersecting channels could fully arrest such leakage. These phe nomena were evaluated both qualitatively from photomicrographs of the fluid flow in the channels and quantitatively from measurements of ele ctrophoretic separations of amino acids and fluoresceins.