Pillar of Engineering Product Development, Singapore University of Technology and Design , Singapore 138682, Singapore.
Anal Chem. 2013 Oct 1;85(19):9126-34. doi: 10.1021/ac4017715. Epub 2013 Sep 9.
A microfluidic device was developed to separate heterogeneous particle or cell mixtures in a continuous flow using acoustophoresis. In this device, two identical surface acoustic waves (SAWs) generated by interdigital transducers (IDTs) propagated toward a microchannel, which accordingly built up a standing surface acoustic wave (SSAW) field across the channel. A numerical model, coupling a piezoelectric effect in the solid substrate and acoustic pressure in the fluid, was developed to provide a better understanding of SSAW-based particle manipulation. It was found that the pressure nodes across the channel were individual planes perpendicular to the solid substrate. In the separation experiments, two side sheath flows hydrodynamically focused the injected particle or cell mixtures into a very narrow stream along the centerline. Particles flowing through the SSAW field experienced an acoustic radiation force that highly depends on the particle properties. As a result, dissimilar particles or cells were laterally attracted toward the pressure nodes at different magnitudes, and were eventually switched to different outlets. Two types of fluorescent microspheres with different sizes were successfully separated using the developed device. In addition, Escherichia coli bacteria premixed in peripheral blood mononuclear cells (PBMCs) were also efficiently isolated using the SSAW-base separation technique. Flow cytometric analysis on the collected samples found that the purity of separated E. coli bacteria was 95.65%.
开发了一种微流控装置，以使用声悬浮在连续流中分离异质颗粒或细胞混合物。在该装置中，由叉指换能器（IDT）产生的两个相同的表面声波（SAW）向微通道传播，从而在通道上建立起驻波声场（SSAW）。开发了一个数值模型，将固体基底中的压电效应和声压耦合起来，以提供对基于 SSAW 的颗粒操纵的更好理解。结果发现，通道中的压力节点是垂直于固体基底的单个平面。在分离实验中，两个侧鞘流通过流体力将注入的颗粒或细胞混合物沿中心线聚焦到非常狭窄的流中。流过 SSAW 场的颗粒会经历强烈依赖于颗粒特性的声辐射力。结果，不同的颗粒或细胞以不同的幅度被侧向吸引到压力节点，并最终被切换到不同的出口。使用开发的装置成功分离了两种具有不同尺寸的荧光微球。此外，使用 SSAW 基分离技术也可以有效地分离外周血单核细胞（PBMCs）中预先混合的大肠杆菌细菌。对收集的样品进行流式细胞术分析发现，分离出的大肠杆菌细菌的纯度为 95.65%。
