MAGNETICALLY CONTROLLED VALVE FOR FLOW MANIPULATION IN POLYMER MICROFLUIDIC DEVICES

摘要

An external in-line valve for use in microfluidic devices constructed of elastomer such as polydimethylsiloxane (PDMS) is described. The valve is actuated by a permanent magnet and a metal bar that press together the polymer walls of a channel. The metal bar is pulled downward by a small NdFeB magnet below the channel, simultaneously pushing the thin layer of PDMS down, closing the channel, and stopping flow of fluid. Operation of the valve is dependent on thickness of the PDMS layer, height of the channel, the gap between chip and magnet, and magnet strength. The valve allows for fabrication of a “thin chip” that allows for detection of chromophoric species within the microchannel via an external fiber optics detection system. C18-Modified reverse phase silica particles are packed into the microchannel using a temporary taper created by the magnetic valve. Separations using both pressure and electrochromatographic driven methods are detailed.