Dielectrophoretic Driving of Blood Cells in a Microchannel

Abstract

Dielectrophoresis is employed in micro total analysis systems to manipulate micro targets in recent years including sorting, transporting, separating, and collecting microparticles for further applications. This research reported a dielectrphoretic trasporting application with interdigitated electrodes and high frequency alternating waves. A kinetic model was proposed to describe the movement of particles in microchannel, which were driven by the DEP force induced by a non-uniform electric field. This electric field was generated by the interdigitated electrodes on the bottom surface of the channel, which transmitted two alternating waves 180 degrees out of phase. Numerical simulation was also utilized to investigate the generated electric field. Both the electric field strength and the gradient of squared electric strength were determined to show the non-uniformity distribution in the channel. Blood cells solution was injected into the dielctrophoretic micro-channel and flow images were recorded to investigate their flow behavior. The experimental results demonstrated the DEP driving force acting upon the sample cells, which changed their orientation and moved in the fluid medium with an obvious acceleration process. Because of the viscosity and friction between the cells and the fluid, a steady flow was formed in the micro-channel. The obtained velocity-time curve of one cell also confirmed the observation by tracing a blood cell flowing in the channel. In this experiment the cell achieved a 4.2 fjm/s flow velocity within 2.3s which remained almost constant in later motion. The experiment also indicated that the moving velocity of the cell was related to the electrode shape, gap, amplitude, and frequency of the applied alternating wave.