Equivalent circuit modeling of electrokinetically driven analytical microsystems

Abstract

Equivalent circuit modeling of microfluidic chips accounts for the transport of fluid and electricity in the entire network of microchannels as a function of the applied pressure and electric potentials. For these calculations, each microchannel is represented by a set of conductance coefficients that relates to driving forces and conjugate flows. Theoretical expressions of the coefficients for rectangular microchannels with arbitrary values of the cross-sectional aspect ratio are derived from the fundamentals of electrokinetic phenomena. Particular emphasis is placed on the analysis of the conditions under which the equivalent circuit model can be accurately employed. Model predictions successfully match data on electrokinetically driven chips for immunoassays reported in the literature. A simulation example is also given to illustrate the capability of the technique for the design and manipulation of analytical microsystems.