Miniaturized shape memory alloy pumps for stepping microfluidic transport

A shape memory alloy (SMA) actuator and a polydimethylsiloxane (PDMS) elastic tube were used to realize a simple pump. A liquid plug in a flow channel could be moved forward and backward reversibly by exploiting the shape memory properties of the actuator. Two SMA sheets were used to create a peristaltic pump capable of moving a solution forward and backward over a long distance. The stepping transport caused by applying pulses of electric power facilitated the adjustment of the plugʹs position. Manipulations such as volume measurement and the merging of two plugs were demonstrated using a microfluidic device with a T-junction.