Micropumping of biofluids by alternating current electrothermal effects

Electrokinetics is a preferred technique for microfluidic systems, but it is typically applied on fluids that are not too conductive (lower than 0.02 S/m), which excludes most biological applications. To solve this problem, this letter investigates microfluidic actuation by ac electrothermal (ACET) effect that was largely overlooked by the community. ACET originates from temperature gradients in the fluids, and it becomes more pronounced in more conductive fluids. This letter discusses two ACET pump designs, and pumping was demonstrated with biobuffers (e.g., lysogeny broth at 0.754 S/m). (c) 2007 American Institute of Physics.