Continuous-flow dielectrophoretic sorting of particles via 3D silicon electrodes featuring castellated sidewalls

Continuous-flow dielectrophoretic sorting of particles has been demonstrated using a simple microfluidic design incorporating 3D electrodes with castellated sidewalls. Two variations of the design have been fabricated, slightly differing in their sidewall and separation junction profiles, through a single-mask process on silicon-based platforms. These 3D silicon electrodes have shown the capacity to segregate polystyrene beads into distinct flow layers along the channel depth while delivering them to separate outlets through a downstream junction of a specific design. The utility of either structure has been showcased by sorting a mixture of 1 and 10 μm beads based on their size continuously at a velocity of 1.5 mm/s.