Opt Lett. 2020 Apr 1;45(7):1998-2001. doi: 10.1364/OL.388188.
Optofluidic manipulation of droplets is critical in droplet-based microfluidic systems for chemistry, biology, and medicine. Here, we reported a thermocapillary microvortices-based manipulation platform for controlling oil-in-water droplets through integrating a photothermal waveguide into a microfluidic chip. The sizes and shapes of the droplets can be controlled by adjusting optical power or positions of the water-oil interface. Here, teardrop-shaped droplets, which can encapsulate and accumulate mesoscopic matters easily, were generated when the water-oil interface and the channel boundaries approached the photothermal waveguide center simultaneously. The results showed that the thermocapillary microvortices have good controllability of droplet positions, droplet volumes, and encapsulated-particle distribution and thus it will be a powerful droplet manipulation strategy for microreactors and microcapsules.
液滴的光流操控在基于液滴的微流控系统中对于化学、生物和医学至关重要。在这里，我们报道了一种基于热毛细微涡旋的操控平台，通过将光热波导集成到微流控芯片中，实现对油包水液滴的控制。通过调整光学功率或油水界面的位置，可以控制液滴的大小和形状。在这里，当水-油界面和通道边界同时接近光热波导中心时，会产生出易于包裹和积累介观物质的泪滴形液滴。结果表明，热毛细微涡旋对液滴位置、液滴体积和包裹粒子分布具有良好的可控性，因此它将成为微反应器和微胶囊的一种强大的液滴操控策略。
