Micro blender and separator using inner-vortex of droplet induced by surface acoustic wave

We report on a micro vortex in a droplet induced by surface acoustic wave acoustic streaming (SAW-AS), which is applicable as a stirrer in micro fluidic devices. Fine controllability of the flow rate in a micro vortex was revealed using two flow-tracking methods with colored aqueous fluids, or scattering laser beams by distributed particles. We performed two practical tasks of a micro stirrer as an on-chip blender and as a separator. Demonstrations results with a small concentrated blood specimen are also shown.