• Electrokinetic injection;
  • EOF;
  • Microfluidics


This paper presents a T-form electrokinetic injection system for the discrete time-based loading and dispensing of samples of variable-volume in a microfluidic chip. A novel push–pull effect is produced during the loading and dispensing processes by the application of an appropriate control voltage distribution. The experimental and numerical results show that this push–pull loading technique produces compact sample plugs and hence improves the detection resolution of the microfluidic device. The injection system is integrated with a microflow switch, and a suitable voltage control scheme is proposed to guide the sample to the desired outlet port such that the microfluidic device can function as a microdispenser. The time-based variable-volume T-form injection method presented in this study is performed using a compact geometry and a simple control scheme and can be readily integrated with other microfluidic devices to form a microfluidic system capable of continuous monitoring and analysis of bioreactions in the life science and biochemistry fields.