MicroPIV study of vortex produced by electrothermal flows inside a microfluidic chamber

Pathogens capture by antigen-antibody recognition reactions is limited by diffusion so that immunoassays typically last a few hours. To accelerate the detection process, the addition of electrohydrodynamic flows in a microsystem is considered. An AC electric voltage applied between coplanar electrodes in a microchannel is demonstrated to produce energy-friendly microfluidics flows that can be used to enhance the detection of low abundance molecules. In a physiological salty liquid sample, the electric forces so generated lead to recirculating flows and to a moderate temperature rise. We present here an experimental study of a quadrupolar flow produced inside a microfluidic chamber. Velocity and vorticity maps obtained by Micro-Particle Image Velocimetry (MicroPIV) are presented and compared to numerical results. It is shown that significant velocities can be obtained.