title: Improvements on the electrokinetic injection technique for microfluidic chips.
abstract: 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.
authors.affiliation: Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chien-Hsien
authors.initials: CH
authors.lastname: Wu
authors.forename: Ruey-Jen
authors.initials: RJ
authors.lastname: Yang
mesh_terms: D046209:Electrophoresis, Microchip; D017022:Flow Injection Analysis / Q000379:methods*; D046210:Microfluidic Analytical Techniques