Dielectrophoretic manipulation and separation of particles in an S-shaped microchannel with hurdles

This paper presents a novel dielectrophoresis

(DEP)-based microfluidic device, which incorporates multiple

round hurdles within an S-shaped curved microchannel for

continuous manipulation and separation of microparticles.

Local nonuniform electric fields are induced by means of both

constricted gaps formed between hurdles and outer channel

wall, and variable current lengths in curved sections with equal

width. Under the effect of negative DEP, particles will be

directed away from either inner wall or hurdle edge, as they

transport throughout the microchannel electrokinetically. Both

experiment and numerical simulation were conducted, the

results of which showed that fix-sized (i.e. 10 or 15 Pm)

polystyrene (PS) particles could be successfully switched,

directed and focused by adjusting applied voltages at inlet and

outlets, and size-based separation of 10 and 15 Pm particles was

achieved with a careful selection of applied voltages. Compared

to other microchannel designs that make use of either obstacle

or curvature individually for inhomogeneous electric fields, this

design offers advantages such as improved controllability over

particle motion, lower requirement of applied voltage, reduced

fouling and particle adhesion, etc.