State of the art acoustofluidics typically treat micro-particles in a multi-wavelength range due to the scale limitations of the established ultrasound field. Here, we report a spatial selective acoustofluidic device that allows trapping micro-particles and cells in a wavelength scale. A pair of interdigital transducers with a concentric-arc shape is used to compress the beam width, while pulsed actuation is adopted to localize the acoustic radiation force in the wave propagating direction. Unlike the traditional usage of geometrical focus, the proposed device is designed by properly superposing the convergent section of two focused surface acoustic waves. We successfully demonstrate a single-column alignment of 15-μm polystyrene particles and double-column alignment of 8-μm T cells in a wavelength scale. Through proof-of-concept experiments, the proposed acoustofluidic device shows potential applications in on-chip biological and chemical analyses, where localized handing is required.

中文翻译：

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用于局部捕集的声流装置的设计。

由于已建立的超声场的规模限制，最先进的声流体技术通常在多波长范围内处理微粒。在这里，我们报告了一种空间选择性的声流装置，该装置可以捕获波长范围内的微粒和细胞。使用一对具有同心圆弧形状的叉指式换能器来压缩波束宽度，同时采用脉冲驱动来将声辐射力定位在波传播方向上。与传统的几何焦点用法不同，所提出的设备是通过适当叠加两个聚焦表面声波的会聚部分而设计的。我们成功地证明的单柱对准15- μ米的聚苯乙烯颗粒和8-双列对齐μ波长范围内的m个T细胞。通过概念验证实验，所提出的声流体装置显示了在需要局部处理的片上生物和化学分析中的潜在应用。