Active microfluidic mixer for mixing of microparticles and liquids

This paper presents a new active microfluidic mixer for mixing of microparticles and liquid samples using electrohydrodynamic (EHD) convection for applications in microfluidic-based biochemical analysis systems and biochips. To understand the EHD convection mixing, analytical analysis on the micro mixer have been performed for two different liquid samples with different electric conductivities. Through the analytical simulation, a new active micro mixer for both liquid/liquid mixing and liquid/microparticles mixing has been designed, fabricated, and demonstrated for application of a magnetic microbead- based analysis system. Magnetic beads that are dispersed in buffer solution have been fully mixed with the selected liquid sample while passing the mixing zone, which has voltage of between 7 to 25 V applied across it. Since the realized micro mixer has simple structure and no mechanically moving parts, it shows very reliable and repeatable mixing performance. The active micro mixing device studied in this work also shows feasible mixing capabilities of microparticles in naon- or pico-liter range of liquid volumes by applying a low voltage of 7 V across the microchannel. Furthermore reliable, robust mixing and manipulating of microparticles in liquid samples can be rapidly achieved.