Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore.
Lab Chip. 2017 May 16;17(10):1769-1777. doi: 10.1039/c7lc00215g.
Acoustic streaming has emerged as a promising technique for refined microscale manipulation, where strong rotational flow can give rise to particle and cell capture. In contrast to hydrodynamically generated vortices, acoustic streaming is rapidly tunable, highly scalable and requires no external pressure source. Though streaming is typically ignored or minimized in most acoustofluidic systems that utilize other acoustofluidic effects, we maximize the effect of acoustic streaming in a continuous flow using a high-frequency (381 MHz), narrow-beam focused surface acoustic wave. This results in rapid fluid streaming, with velocities orders of magnitude greater than that of the lateral flow, to generate fluid vortices that extend the entire width of a 400 μm wide microfluidic channel. We characterize the forces relevant for vortex formation in a combined streaming/lateral flow system, and use these acoustic streaming vortices to selectively capture 2 μm from a mixed suspension with 1 μm particles and human breast adenocarcinoma cells (MDA-231) from red blood cells.
声流已成为一种很有前途的微尺度操纵技术，在该技术中，强旋流可实现对粒子和细胞的捕获。与由流体动力学产生的涡旋不同，声流可快速调节，具有高度可扩展性，且不需要外部压力源。尽管在大多数利用其他声流效应的声流系统中，声流通常被忽略或最小化，但我们通过使用高频（381MHz）、窄波束聚焦表面声波在连续流中最大限度地增强声流效应。这会产生快流速，其量级比横向流速大几个数量级，从而产生可延伸至整个 400μm 宽微流道宽度的流体涡旋。我们在结合了声流/横向流的系统中对与涡旋形成相关的力进行了表征，并利用这些声流涡旋从混合悬浮液中选择性捕获 2μm 的微球和来自红细胞的人乳腺癌腺癌细胞（MDA-231）。
