Dielectrophoretic Analysis of Polystyrene Spheres in Fluidic Suspension

Abstract

Polystyrene spheres, suspended in deionized water, flowing in a microfluidic channel are actuated using a non-uniform electric field, with the final goal of determining the dielectrophoretic (DEP) force spectra of the particles. Particle height changes are detected by measuring the capacitance of set of electrodes at high frequency (1.58 GHz). Two sets of DEP experiments are analyzed for applied DEP signals ranging in frequency from 50 kHz to 10 MHz. For one experiment, a simulated mapping is found to determine the Clausius-Mossotti factor, a frequency dependent term in the DEP force equation, for each particle in the data set. Remaining experiments are analyzed by plotting the normalized height change, a measure of the relative change in height of each particle as an indication of the DEP force.