title: Numerical studies of electrokinetic control of DNA concentration in a closed-end microchannel.
abstract: A major challenge in lab-on-a-chip devices is how to concentrate sample molecules from a dilute solution, which is critical to the effectiveness and the detection limit of on-chip bio-chemical reactions. A numerical study of sample concentration control by electrokinetic microfluidic means in a closed-end microchannel is presented in this paper. The present method provides a simple and efficient way of concentration control by using electrokinetic trapping of a charged species of interest, controlling liquid flow and separating different sample molecules in the microchannel. The electrokinetic-concentration process and the controlled transport of the sample molecules are numerically studied. In this system, in addition to the electroosmotic flow and the electrophoresis, the closed-end of the chamber causes velocity variation at both ends of the channel and induces a pressure gradient and the associated fluid movement in the channel. The combined effects determine the final concentration field of the sample molecules. The influences of a number of parameters such as the channel dimensions, electrode size and the applied electric field are investigated.
authors.affiliation: Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada.
authors.forename: Yasaman
authors.initials: Y
authors.lastname: Daghighi
authors.forename: Dongqing
authors.initials: D
authors.lastname: Li
mesh_terms: D004247:DNA / Q000737:chemistry*; D004574:Electromagnetic Fields; D046209:Electrophoresis, Microchip / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008956:Models, Chemical
chemical_list: D004247:DNA