Sheathless Focusing and Separation of Microparticles Using Tilted-Angle Traveling Surface Acoustic Waves
Sheathless Focusing and Separation of Microparticles Using Tilted-Angle Traveling Surface Acoustic Waves
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DOI：
10.1021/acs.analchem.8b01593
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发表时间：
2018-07-17
影响因子：
7.4
通讯作者：
Sung, Hyung Jin
中科院分区：
文献类型：
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作者：
Ahmed, Husnain;Destgeer, Ghulam;Sung, Hyung Jin
微粒的无鞘聚焦和分离是各种生化测定中的重要预处理步骤，其中富集样品分离是关键的。大多数先前的微流体颗粒分离技术已经使用鞘流来实现有效的样品聚焦。鞘流稀释了分析物，需要额外的微通道和精确的流量控制。我们展示了一个倾斜角行进表面声波（taTSAW）为基础的无鞘聚焦和分离的颗粒在连续流。所提出的装置由压电基板与一对叉指换能器（IDT）沉积在两个不同的角度相对于流动方向。将具有一个入口和两个出口的Y形聚二甲基硅氧烷（PDMS）微通道定位在IDT的顶部上，使得耦合到流体中的声能最大化，并且PDMS壁的波衰减最小化。两个IDT独立地产生高频taTSAW，其相对于流动方向以+/-30度传播，并将直接的声辐射力施加到目标颗粒上。将4.8和3.2 μ m颗粒的样品混合物聚焦，然后分别在194和136 MHz频率下通过IDT的致动分离，而不使用额外的鞘流。所提出的基于taTSAW的颗粒分离装置在宽范围的流速（高达83.3mm/s）下在两个出口处提供>99%的高纯度。
Sheathless focusing and separation of microparticles is an important preprocessing step in various biochemical assays in which enriched sample isolation is critical. Most of the previous microfluidic particle separation techniques have used sheath flows to achieve efficient sample focusing. The sheath flow dilutes the analyte and requires additional microchannels and accurate flow control. We demonstrated a tilted-angle traveling surface acoustic wave (taTSAW)-based sheathless focusing and separation of particles in a continuous flow. The proposed device consists of a piezoelectric substrate with a pair of interdigitated transducers (IDTs) deposited at two different angles relative to the flow direction. A Y-shaped polydimethylsiloxane (PDMS) microchannel having one inlet and two outlet ports was positioned on top of the IDTs such that the acoustic energy coupling into the fluid was maximized and wave attenuation by the PDMS walls was minimized. The two IDTs independently produced high-frequency taTSAWs, which propagated at +/- 30 degrees with respect to the flow direction and imparted a direct acoustic radiation force onto the target particles. A sample mixture of 4.8 and 3.2 mu m particles was focused and then separated by the actuation of the IDTs at 194 and 136 MHz frequencies, respectively, without using an additional sheath flow. The proposed taTSAW-based particle separation device offered a high purity >99% at the both outlets over a wide range of flow speeds (up to 83.3 mm/s).