Dielectrophoretic cell concentrator on EWOD-Based chips

Dielectrophoretic concentrators were successfully developed on a EWOD-based chip. In such a chip, two major electrokinetic forces were exerted on objects on different scales. EWOD is used to pump droplets on a mm scale, while DEP manipulates bio-particles on a pm scale. Both cells and polystyrene beads were used to demonstrate the concentration abilities by pDEP and nDEP forces, respectively. Since electrodes are covered with a dielectric layer, instead of creating nonuniform electric fields in the liquid, low frequency signals are consumed in the dielectric layer and providing EWOD. It is necessary to use high frequency signals to generate DEP on a EWOD-based chip. Concentration efficiency, measured by cell count chamber before and after experiments, is around 1.62 with single cycle of pDEP attraction.