On-chip integration of a microfluidic valve and pump for sample acquisition and movement

摘要

We report on the on-chip integration of a valve and pump for acquiring microfluidic samples and moving them through micro-channels. The valve employs temperature-sensitive hydrogels which are controlled by micro-heaters. The pump is a nickel rotor actuated magnetically by an external rotating magnet. The valve is fabricated as a series of hydrogel rings spaced within microfluidic channels. The expanded state of the hydrogel cylinders at low temperatures blocks liquid flow. Upon application of heat, the hydrogels contract in volume allowing liquid to flow through them. The pump brings about a recirculating movement of the liquid within the microchannel due to the rotation of the nickel rotor. The device is fabricated by combining liquid phase photopolymerization of structural polymers and temperature responsive hydrogels, with nickel electroplating. The valve has a response time of ～　45 s and the pump generates a flow rate of ～　1 μL/min.