Active liquid aspiration and dispensing based on an expanding PDMS composite

In this work we present the development of a liquid aspiration and dispensing unit which is based on a single- use thermally expanding PDMS composite. The composite actuator consists of expandable microspheres incorporated into a PDMS matrix and allows for locally altering its topography by means of individually addressable integrated heaters. Devices were designed in order to enable the generation of a cavity by the expansion of the composite actuator and are entirely fabricated from low-cost materials using wafer-level processes only. The fabricated devices successfully demonstrated controlled liquid aspiration and release thereafter of liquid volumes ranging from 180 nl to 815 nl.