Microparticles manipulation and enhancement of their separation in pinched flow fractionation by insulator-based dielectrophoresis.

The separation and manipulation of microparticles in lab on a chip devices have importance in point of care diagnostic tools and analytical applications. The separation and sorting of particles from biological and clinical samples can be performed using active and passive techniques. In passive techniques, no external force is applied while in active techniques by applying external force (e.g. electrical), higher separation efficiency is obtained. In this article, passive (pinched flow fractionation) and active (insulator-based dielectrophoresis) methods were combined to increase the separation efficiency at lower voltages. First by simulation, appropriate values of geometry and applied voltages for better focusing, separation, and lower Joule heating were obtained. Separation of 1.5 and 6 μm polystyrene microparticles was experimentally obtained at optimized geometry and low total applied voltage (25 V). Also, the trajectory of 1.5 μm microparticles was controlled by adjusting the total applied voltage.