A simple low-cost yet versatile microtechnology I platform is demonstrated as capable of performing a variety of microfluidic actuation functions including on-chip pumping, mixing, cell/particle sorting, and sample extraction. This technology termed air liquid cavity acoustic transducers (ALCATs) uses trapped air bubbles as the functional elements. When an external acoustic energy source is applied to the device, the trapped bubbles oscillate, generating acoustic streaming within the fluid. By controlling their relative position and angle with the liquid channel/chamber, the ALCAT can push away or pull in the surrounding liquid contents and its contained particulates. In this report, we provide a general introduction of the ALCAT microtechnology platform and its application to enhancing biomolecular assays. (JALA 2010; 15:449-54)