Concentrating molecules in a simple microchannel

A simple method is proposed and tested to concentrate sample molecules from a dilute solution in a microchannel by electrokinetic means. The microfluidic chip has a straight microchannel connecting two wells and three electrodes. This method uses electrokinetic trapping and flow control simultaneously to concentrate a charged species of interest. A numerical model of the sample concentration process is presented in this paper. Using a fluorescent dye as the sample molecules, experimental investigation into the concentration process was performed. The 90 times of the concentration increase was achieved in 110 s. The numerical simulations of the concentrating and the subsequent dispensing processes agree well with the experimental results.

Graphical abstractConcentrating sample molecules from a dilute solution in a microfluidic channel by electrokinetic means.Figure optionsDownload full-size imageDownload high-quality image (72 K)Download as PowerPoint slide