Recent advances in direct current electrokinetic manipulation of particles for microfluidic applications

Microfluidic devices have been extensively used to achieve precise transport and placement of a variety of particles for numerous applications. A range of force fields have thus far been demonstrated to control the motion of particles in microchannels. Among them, electric field-driven particle manipulation may be the most popular and versatile technique because of its general applicability and adaptability as well as the ease of operation and integration into lab-on-a-chip systems. This article is aimed to review the recent advances in direct current (DC) (and as well DC-biased alternating current) electrokinetic manipulation of particles for microfluidic applications. The electric voltages are applied through electrodes that are positioned into the distant channel-end reservoirs for a concurrent transport of the suspending fluid and manipulation of the suspended particles. The focus of this review is upon the cross-stream nonlinear electrokinetic motions of particles in the linear electroosmotic flow of fluids, which enable the diverse control of particle transport in microchannels via the wall-induced electrical lift and/or the insulating structure-induced dielectrophoretic force.