Cross-channel microfluidic device for dynamic control of concentration and velocity by the electroosmotic drive

Abstract

Accurate and fast control of fluid flow velocity and mixing is an essential technique for in vitro cell or microbial culture. Here, we propose a cross microchannel structure based on electroosmotic drive, which enables efficient cooperative dynamic control of fluid velocity and concentration. In this study, the effects of channel width, applied voltage, and waveform on fluid mixing and flow behavior in microchannels are investigated experimentally and numerically. We find that the flow velocity and the fluid mixing ratio can be efficiently regulated by the applied voltage. Moreover, reducing the width of one of the microchannels can significantly improve the control accuracy of the fluid mixing ratio in the system. We also find that various concentration and velocity waveforms can be generated by controlling the voltage waveform. Our results reveal some important features of electroosmotic-driven flow that could facilitate the design of electrically operated fluid devices.