Research on applying constant current to control the EOF in microfluidic chips

Abstract

The difference of controlling the electroosmotic flow (EOF) in microchip electrophoresis between applied constant current and constant voltage is compared in this paper. We can deduce that the current in microchannels indicates the velocity of the EOF more directly than the voltage applied on reservoirs. So controlling the EOF in microchip electrophoresis by the current in microchannels will be more convenient than applying voltage on reservoirs. A constant voltage/current dual-function high voltage power supply (HV power supply) has been designed with Micro-Computer Control Unit (MCU) for our study. The HV power supply has quadruple outputs. The PMMA microfluidic chips with double T layout are used in the experiments of microchip electrophoresis in this paper. They are applied with constant current control mode and constant voltage control mode respectively. In result, the same current program has better adaptability than the voltage program to microfluidic chips with different size.