Department of Applied Physics, KTH Royal Institute of Technology, Roslagstullsbacken 21, SE-114 21 Stockholm, Sweden.
Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark.
J Acoust Soc Am. 2021 Mar;149(3):1445. doi: 10.1121/10.0003600.
Acoustic trapping is a promising technique for aligning particles in two-dimensional arrays, as well as for dynamic manipulation of particles individually or in groups. The actuating principles used in current systems rely on either cavity modes in enclosures or complex arrangements for phase control. Therefore, available systems either require high power inputs and costly peripheral equipment or sacrifice flexibility. This work presents a different concept for acoustic trapping of particles and cells that enables dynamically defined trapping patterns inside a simple and inexpensive setup. Here, dynamic operation and dexterous trapping are realized through the use of a modified piezoelectric transducer in direct contact with the liquid sample. Physical modeling shows how the transducer induces an acoustic force potential where the conventional trapping in the axial direction is supplemented by surface displacement dependent lateral trapping. The lateral field is a horizontal array of pronounced potential minima with frequency-dependent locations. The resulting system enables dynamic arraying of levitated trapping sites at low power and can be manufactured at ultra-low cost, operated using low-cost electronics, and assembled in less than 5 min. We demonstrate dynamic patterning of particles and biological cells and exemplify potential uses of the technique for cell-based sample preparation and cell culture.
声捕获是一种很有前途的技术，可以将粒子排列成二维阵列，也可以单独或成组地动态操纵粒子。目前系统中使用的驱动原理要么依赖于外壳中的腔模，要么依赖于相位控制的复杂布置。因此，现有的系统要么需要高功率输入和昂贵的外围设备，要么牺牲灵活性。这项工作提出了一种用于粒子和细胞声捕获的新概念，它可以在简单且廉价的设置内实现动态定义的捕获模式。在这里，通过使用与液体样品直接接触的改良压电换能器，实现了动态操作和灵活的捕获。物理建模展示了换能器如何感应声力势，其中传统的轴向捕获由表面位移相关的横向捕获补充。横向场是具有频率相关位置的明显势极小值的水平阵列。由此产生的系统可以在低功率下实现悬浮捕获位置的动态排列，并且可以以超低的成本制造，使用低成本的电子设备操作，并且可以在不到 5 分钟的时间内组装。我们演示了粒子和生物细胞的动态图案，并举例说明了该技术在基于细胞的样品制备和细胞培养中的潜在用途。
