Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P.R. China.
Lab Chip. 2020 Oct 7;20(19):3544-3551. doi: 10.1039/d0lc00641f. Epub 2020 Sep 8.
A surface wetting-driven droplet generation microfluidic chip was developed, and could produce droplets spontaneously once adding a drop of oil and an aqueous sample on the chip without any power source and equipment. The chip is simply composed of three drilled holes connected by a single microchannel. The aqueous sample dropped in the middle hole could be converged and segmented into monodispersed droplets spontaneously by preloading oil in the side hole, and then flow into the other side hole through the microchannel. To address the high throughput and stability in practical applications, a siphon pump was further integrated into the microfluidic chip by simply connecting oil-filled tubing also acting as a collector. In this way, droplets can be generated spontaneously with a high uniformity (CV < 3.5%) and adjustable size (30-80 μm). Higher throughput (280 Hz) and multi-sample emulsification are achieved by parallel integration of a multi-channel structure. Based on that, the microfluidic chip was used as the droplet generator for the ddPCR to absolutely quantify S. mutans DNA. This is the first time that the feasibility of droplet generation driven only by oil wettability on hydrophobic surfaces is demonstrated. It offers great opportunity for self-sufficient and portable W/O droplet generation in biomedical samples, thus holding the potential for point-of-care testing (POCT).
一种基于润湿性驱动的液滴生成微流控芯片被开发出来，只需在芯片上滴加一滴油和水性样品，无需任何电源和设备即可自发产生液滴。该芯片由三个通过单个微通道连接的钻孔简单组成。中间孔中滴入的水性样品可以通过预加载侧孔中的油自发汇聚和分割成单分散液滴，然后通过微通道流入另一侧孔。为了解决实际应用中的高通量和稳定性问题，通过简单地连接充油管道（也作为收集器）将蠕动泵进一步集成到微流控芯片中。通过这种方式，可以自发地生成具有高均匀性（CV<3.5%）和可调节尺寸（30-80μm）的液滴。通过并行集成多通道结构实现了更高的通量（280Hz）和多样品乳化。在此基础上，该微流控芯片被用作 ddPCR 的液滴发生器，以绝对定量 S. mutans DNA。这是首次证明仅由疏水性表面的润湿性驱动的液滴生成的可行性。它为在生物医学样本中实现自给自足和便携式 W/O 液滴生成提供了巨大机会，因此具有即时检测（POCT）的潜力。
