Concentration of microbubbles with surface acoustic wave devices

An effective technique to concentrate the lipid-coated microbubbles within a droplet based on the surface acoustic wave is demonstrated. A droplet was partially placed on a surface acoustic wave propagation path, and microbubbles were concentrated at the center of the droplet due to the asymmetry. The device consist a lithium niobate piezoelectric substrate and a pair of interdigital transducer electrodes for SAW excitation and detection. The concentrate rate increases as improving the input power or the concentration of microbubbles. This method would have potential applications on drug screening, bioassays, and other biomedical devices.