Use of isoelectric focusing for sample preconditioning in a microfluidic electrochemical flow cell

A novel free-flow isoelectric focusing (IEF) implementation method has been developed, called /spl mu/IEF, as part of a larger effort to design microfluidic sample preconditioning techniques. The /spl mu/IEF method consists of a novel device in which the electrodes are in intimate contact with the bulk fluid and pH gradient formation is driven by the products of electrolysis generated at the electrodes. The /spl mu/IEF flow cell is fabricated using rapid prototyping techniques. /spl mu/IEF has been used successfully to concentrate vegetative bacteria and proteins. The thickness and position of the focused band can be adjusted by varying the buffer composition and the initial pH.