AC Insulator-Based Dielectrophoretic Separation of Live and Dead Yeast Cells

The separation of live and dead cells is crucial for the diagnosis of early-stage diseases and efficacy test of drug screening, etc. We demonstrate the biological application of our recently developed AC insulator-based dielectrophoresis (AC iDEP) technique for the separation of live and dead yeast cells in a virtually infinitely long ratchet microchannel. This separation arises from the variation of surface charge and in turn electrokinetic velocity when yeast cells lose viability, as compared to the varying dielectrophoretic responses in conventional dielectrophoretic methods. The live and dead yeast cells can be focused toward the channel centerline and ratchet base, respectively, under AC voltages within a selected frequency and amplitude window. The performance of this cell viability-based AC iDEP separation is evaluated using the separation efficiency, which is reasonably predicted by a numerical model.