Real-time control of inertial focusing in microfluidics using dielectrophoresis (DEP)

In this paper we propose a novel hybrid microfluidic device which, for the first time, integrates and fully couples both dielectrophoresis (DEP) and inertial focusing. A DEP force is coupled with inertial lift force to adjust particle equilibrium positions in the vertical direction in real time. The focusing pattern and position of the particles along the horizontal plane can be adjusted concurrently by adjusting their vertical position with DEP forces. The magnitude of secondary flow drag increases dramatically when particles are levitated towards the centre of the channel in the vertical direction. The paper investigates the mechanism of this tuneable DEP-inertial microfluidic device analytically and experimentally. The proposed hybrid device possesses the advantages of both DEP and inertial microfluidic devices, working in a high-throughput manner as well as having precise controllability in real-time. This DEP-inertial microfluidic device is potentially a versatile and robust platform for feedback-controlled manipulation and separation of particles and cells.Full Tex