Dielectrophoretic Actuation and Simultaneous Detection of Individual Bioparticles

A microflow cytometer uses a microelectrode array to simultaneously actuate and detect biological particles. Applied microelectrode array potentials in the 10-1000 kHz band generate a dielectrophoretic force which actuates passing bioparticles. Cells are detecting using two independent methods: (1) optical cell assay, in which the change in cellular velocity due to the dielectrophoretic and fluid drag forces is estimated from digital video of the microelectrode array region; and (2) capacitive cytometry, in which a 1.478 GHz coupled capacitance sensor produces a sense signal proportional to the transient capacitance perturbations induced by passing bioparticles. The results obtained from these two independent methods support one another. This work primarily studies baker’s yeast (Saccharomyces cerevisiae) cells. Additional studies of Chinese Hamster Ovary cells and polystyrene spheres are also presented.