Single-use microfluidic pumps and valves based on a thermally responsive PDMS composite

In this work we present active microfluidic liquid handling integrated on-chip with no need for external actuators. The concept is based on a temperature sensitive silicone elastomer composite, consisting of PDMS and expandable microspheres. We successfully fabricated single-use microfluidic pumps and displaced liquids in the range of nanoliters even against counter pressures up to 100kPa. Moreover, liquid flow in a microchannel was entirely blocked by means of integrated valves. The valves could withstand pressures up to 140kPa. The devices were fabricated entirely from low cost materials and allow wafer-level processing to be used.