Huang Laixin, Zhou Juan, Kong Deqing, Li Fei
Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
Muroran Institute of Technology, Muroran 050-8585, Hokkaido, Japan.
Micromachines (Basel). 2022 Dec 9;13(12):2181. doi: 10.3390/mi13122181.
Sieving specific particles from mixed samples is of great value in fields such as biochemistry and additive manufacturing. In this study, a particle sieving method for microfluidics was proposed based on a phononic crystal plate (PCP), the mechanism of which originates from the competition between the trapping effect of the resonant PCP-induced acoustic radiation force (ARF), disturbance effect of acoustic streaming (AS), and flushing effect of the continuous inlet flow on particles suspended in microfluidic channels. Specifically, particles with different sizes could be separated under inlet flow conditions owing to ARF and AS drag forces as functions of the particle diameter, incident acoustic pressure, and driving frequency. Furthermore, a comprehensive numerical analysis was performed to investigate the impacts of ARF, AS, and inlet flow conditions on the particle motion and sieving efficiency, and to explore proper operating parameters, including the acoustic pressure and inlet flow velocity. It was found that, for each inlet flow velocity, there was an optimal acoustic pressure allowing us to achieve the maximum sieving efficiency, but the sieving efficiency at a low flow velocity was not as good as that at a high flow velocity. Although a PCP with a high resonant frequency could weaken the AS, thereby suiting the sieving of small particles (<5 μm), a low channel height corresponding to a high frequency limits the throughput. Therefore, it is necessary to design a PCP with a suitable resonant frequency based on the size of the particles to be sieved. This investigation can provide guidance for the design of massive acoustic sorting mi-crofluidic devices based on phononic crystals or acoustic metamaterials under continuous flow.
从混合样本中筛选特定颗粒在生物化学和增材制造等领域具有重要价值。在本研究中，提出了一种基于声子晶体板（PCP）的微流控颗粒筛分方法，其原理源于共振PCP诱导的声辐射力（ARF）的捕获效应、声流（AS）的干扰效应以及连续入口流对微流控通道中悬浮颗粒的冲洗效应之间的竞争。具体而言，由于ARF和AS拖曳力是颗粒直径、入射声压和驱动频率的函数，不同尺寸的颗粒在入口流条件下可以被分离。此外，进行了全面的数值分析，以研究ARF、AS和入口流条件对颗粒运动和筛分效率的影响，并探索合适的操作参数，包括声压和入口流速。研究发现，对于每个入口流速，都存在一个最佳声压，使我们能够实现最大筛分效率，但低流速下的筛分效率不如高流速下的好。尽管具有高共振频率的PCP可以减弱AS，从而适合筛分小颗粒（<5μm），但与高频对应的低通道高度限制了通量。因此，有必要根据待筛分颗粒的尺寸设计具有合适共振频率的PCP。本研究可为基于声子晶体或声学超材料的大规模声学分选微流控装置在连续流条件下的设计提供指导。
