A novel fluidic actuator that is simple to fabricate, integrate, and operate is demonstrated for use within microfluidic systems. The actuator is designed around the use of trapped air bubbles in lateral cavities and the resultant acoustic streaming generated from an outside acoustic energy source. The orientation of the lateral cavities to the main microchannel is used to control the bulk fluid motion within the device. The first order flow generated by the oscillating bubble is used to develop a pumping platform that is capable of driving fluid within a chip. This pump is integrated into a recirculation immunoassay device for enhanced biomolecule binding through fluid flow for convection limited transport. The recirculation system showed an increase in binding site concentration when compared with traditional passive and flow-through methods. The acoustic cavity transducer has also been demonstrated for application in particle switching. Bursts of acoustic energy are used to generate a second order streaming pattern near the cavity interface to drive particles away or towards the cavity. The use of this switching mechanism is being extended to the application of sorting cells and other particles within a microfluidic system.

Date Published: 12 February 2010
PDF: 6 pages
Proc. SPIE 7574, Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications VII, 757402 (12 February 2010); doi: 10.1117/12.851040

Published in SPIE Proceedings Vol. 7574:
Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications VII
Alexander N. Cartwright; Dan V. Nicolau, Editor(s)