Medically Advanced Devices Lab, Center for Medical Devices, Department of Mechanical and Aerospace Engineering, Jacobs School of Engineering and Department of Surgery, School of Medicine, 9500 Gilman Dr. MC0411 University of California San Diego La Jolla CA 92093 USA.
Adv Sci (Weinh). 2021 May 16;8(13):2100408. doi: 10.1002/advs.202100408. eCollection 2021 Jul.
Controllable manipulation and effective mixing of fluids and colloids at the nanoscale is made exceptionally difficult by the dominance of surface and viscous forces. The use of megahertz (MHz)-order vibration has dramatically expanded in microfluidics, enabling fluid manipulation, atomization, and microscale particle and cell separation. Even more powerful results are found at the nanoscale, with the key discovery of new regimes of acoustic wave interaction with 200 fL droplets of deionized water. It is shown that 40 MHz-order surface acoustic waves can manipulate such droplets within fully transparent, high-aspect ratio, 100 nm tall, 20-130 micron wide, 5-mm long nanoslit channels. By forming traps as locally widened regions along such a channel, individual fluid droplets may be propelled from one trap to the next, split between them, mixed, and merged. A simple theory is provided to describe the mechanisms of droplet transport and splitting.
受表面张力和粘性力的支配，纳米尺度下对流体和胶体进行可控操作和有效混合变得异常困难。兆赫兹（MHz）量级的振动在微流控领域的应用得到了极大的扩展，实现了对流体的操控、雾化以及微尺度颗粒和细胞的分离。在纳米尺度上，人们发现了更强大的结果，关键在于发现了与去离子水 200fL 液滴相互作用的新声波波导模式。结果表明，40MHz 量级的表面声波可以在完全透明、高纵横比、100nm 高、20-130μm 宽、5mm 长的纳米缝隙通道中操控这些液滴。通过在这样的通道中形成局部变宽的区域作为陷阱，可以将单个液滴从一个陷阱推进到另一个陷阱，在它们之间分裂、混合和合并。提供了一个简单的理论来描述液滴传输和分裂的机制。
