Acoustically Driven Programmable Microfluidics for Biological and Chemical Applications

A novel approach toward the needs of a versatile chip-based microfluidic system with unique properties and functionality is reviewed. Like for microarrays and in contrast to many existing technologies, the fluid handling is performed on the flat surface of a programmable chip, where fluidic tracks and functional blocks such as valves, dispensers, mixers, and sensing elements are chemically defined using standard lithographic techniques. The actuation of the fluid, the driving and addressing of the functional elements as well as possible sensors are based on electrically excited mechanical surface acoustic waves, propagating along the surface of a chip. Based on this acoustically driven microfluidic technique, a variety of different chips but also lab equipment has been devised, including a chip-based PCR reactor, microarray hybridization chambers, and noninvasive miniature mixers for cuvette and micro titerplate applications.