Separation of live and dead yeast cells using AC insulator-based dielectrophoresis

Insulator-based dielectrophoresis (iDEP) is an emerging technique for particle and cell handling in microfluidic devices. It utilizes the electric field gradients induced by insulating structures to generate negative or positive DEP. We report in this work a separation of live and dead yeast cells in a ratchet microchannel using AC iDEP. By tuning the AC field frequency, we achieve the positive dielectrophoretic motion of live cells towards the tips of the ratchets, where the electric field is locally the highest. In contrast, dead cells undergo a negative dielectrophoretic motion towards the bases of the ratchets, where the electrical field is locally the lowest. We also examine how the variation of AC field amplitude affects the frequency range for this viability-based cell separation. Moreover, we investigate if a DC bias can be added to the electric field for achieving a continuous-flow separation.