The Study of Microfluidic Chip with Micro Cylindrical Post Array for Separating Particles

This study presents the design, simulation, fabrication and measurement of a microfluidic chip with micro cylindrical post array for separating particles. The structure of microfluidic chip is consisted of top glass, a micro channel with cylindrical post array, two Au end electrodes and bottom glass. Both in-line and staggered arrays of micro cylindrical posts were designed and made of SU-8 inside the micro channel by MEMS technology. The simulated results showed that the applied DC voltage at the end electrodes would generate a non-uniform electric field within the array of cylindrical posts, and particles would be attracted there. From the results of experiment, the minimum required DC voltages to drive micro particles flowing into the micro channel by electrokinetic effect were 15V and 30V, respectively, at the electrode spacing of 8mm and 25mm for both array types. Under the dielectrophoretic effect created by the non-uniform electric field, the latex particles could be concentrated around micro cylindrical posts with electric field intensity minima and separated from flowing fluid. This phenomenon is in agreement with the simulation.