Electro-osmotic flow control for living cell analysis in microfluidic PDMS chips

This study presents a microfluidic PDMS platform for multiplex cell culture applications. This platform includes two cell culture lines each of which consists of an integrated electro-osmotic pump, a cell culture chamber and a series of microchannels and reservoirs. Each integrated electro-osmotic pump consists of 70 parallel channels of 50 μm wide × 2.7 μm high, two electrode reservoirs and two gel salt bridges separating the electrode reservoirs and the parallel microchannels. In this design, efforts were made to address the problems associated with the use of high electric fields required for operating electro-osmotic pumps in living cell analysis. In particular, electroporation of cell membranes, Joule heating, electrolysis, bubbles and induced pressure disturbance were carefully considered through the design of the platform. The integrated electro-osmotic pumps allow the platform to be operated in three differential modes aiming to achieve flexible flow rate control and accurate injection of a small amount of reagent both of which are important for dynamic studies of cells.