Real-time impedance-activated dielectrophoretic actuation for reconfigurable manipulation of single flowing particles†

This work presents an innovative all-electrical platform for selective single-particle manipulation. The platform combines microfluidic impedance cytometry for label-free particle characterization and dielectrophoresis for contactless multi-way particle separation. The microfluidic chip has a straightforward coplanar electrode layout and no particle pre-focusing mechanism is required. An original online algorithm analyzes the impedance signals of each incoming particle and regulates in real time the dielectrophoretic voltages according to a desired control logic. As a proof-of-concept, three operation modes are demonstrated on a mixture of 8, 10, and 12 μm diameter beads: (i) particle position swapping across the channel axis, irrespective of particle size, (ii) size-based particle separation, irrespective of particle position, and (iii) sorting of a selected sequence of particles. As a perspective, the versatility of impedance cytometry and dielectrophoresis, and the possibility of configuring alternative control logics, hold promise for advanced particle and cell manipulation.