A millisecond micromixer viasingle-bubble-based acoustic streamingElectronic supplementary information (ESI) available: Device fabrication and calculation details, and videos for Fig. 1 to Fig. 3. See DOI: 10.1039/b903687c.

We present ultra-fast homogeneous mixing inside a microfluidic channel viasingle-bubble-based acoustic streaming. The device operates by trapping an air bubble within a “horse-shoe” structure located between two laminar flows inside a microchannel. Acoustic waves excite the trapped air bubble at its resonance frequency, resulting in acoustic streaming, which disrupts the laminar flows and triggers the two fluids to mix. Due to this technique's simple design, excellent mixing performance, and fast mixing speed (a few milliseconds), our single-bubble-based acoustic micromixer may prove useful for many biochemical studies and applications. [ABSTRACT FROM AUTHOR]