The effects of microstructures on a dielectrophoretic chip for trapping particles

A dielectrophoretic (DEP) chip with an SU-8 microcavity array for trapping single particle/cell is designed, fabricated, and quantitatively examined by simulations and experiments. The particles can be easily trapped in or pulled out of the microcavity based on negative or positive DEP force, respectively. The nonuniform electric field is formed in relation to the configuration of the microcavity array, i.e. its diameter and spacing, as described in the simulation results. In order to investigate the effects of the microcavity, two maximal flow rates for trapping particles in the microcavity and washing them away from the microcavity under different DEP voltages are determined by experiments. As the experimental results show, the extrastationary effects, provided as a particle is trapped in the microcavity, mean that the trapped particle can sustain a low flow rate even without applying DEP voltage. Consequently, this DEP chip is suitable for long-term monitoring of trapped cells by supplying the subsisting buffer at a low flow rate without the damage or heating effect caused by DEP voltage.