Microfluidic schemes using electrical and capillary forces

Abstract

The laboratory-on-a-chip (LOC) and indeed virtually all the technology of microTAS (micro-total-analysis systems) rely upon some microfluidic subsystem to control, transport, and manipulate small liquid masses. The most promising of these subsystems use electrical forces, which have the advantages of voltage-based control and dominance over gravity and capillarity in the 10 to 103 micron diameter range. Gravity is usually ignorable on this scale, but the interactions of electrical and capillary forces are more complex. In particular, microstructures can be designed to exploit this interplay for the cases of electrowetting on dielectric-coated electrodes (EWOD) and liquid dielectrophoresis (DEP). The complementary nature of the two effects explains the operation of droplet-based microfluidic systems in general, and the so-called DEP droplet dispenser in particular. © 2008 IOP Publishing Ltd.