Meng Xiangkai, Yu Yuanhua, Jin Guangyong
School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022, China.
School of Science, Changchun University of Science and Technology, Changchun 130022, China.
Micromachines (Basel). 2021 Apr 7;12(4):409. doi: 10.3390/mi12040409.
The generation of droplets is one of the most critical steps in the droplet digital polymerase chain reaction (ddPCR) procedure. In this study, the mechanism of droplet formation in microchannel structure and factors affecting droplet formation were studied. The physical field of laminar two-phase flow level was used to simulate the process of droplet generation through microfluidic technology. The effect of the parameters including flow rate, surface tension, and viscosity on the generated droplet size were evaluated by the simulation. After that, the microfluidic chip that has the same dimension as the simulation was then, fabricated and evaluated. The chip was made by conventional SU-8 photolithography and injection molding. The accuracy of the simulation was validated by comparing the generated droplets in the real scenario with the simulation result. The relative error (RE) between experimentally measured droplet diameter and simulation results under different flow rate, viscosity, surface tension and contact angle was found less than 3.5%, 1.8%, 1.4%, and 1.2%, respectively. Besides, the coefficient of variation (CV) of the droplet diameter was less than 1%, which indicates the experimental droplet generation was of high stability and reliability. This study provides not only fundamental information for the design and experiment of droplet generation by microfluidic technology but also a reliable and efficient investigation method in the ddPCR field.
液滴生成是数字液滴聚合酶链反应（ddPCR）过程中最关键的步骤之一。在本研究中，对微通道结构中液滴形成的机制以及影响液滴形成的因素进行了研究。利用层流两相流水平的物理场，通过微流控技术模拟液滴生成过程。通过模拟评估了流速、表面张力和粘度等参数对生成液滴尺寸的影响。之后，制作并评估了与模拟具有相同尺寸的微流控芯片。该芯片采用传统的SU-8光刻和注塑成型工艺制作。通过将实际场景中生成的液滴与模拟结果进行比较，验证了模拟的准确性。发现在不同流速、粘度、表面张力和接触角下，实验测量的液滴直径与模拟结果之间的相对误差（RE）分别小于3.5%、1.8%、1.4%和1.2%。此外，液滴直径的变异系数（CV）小于1%，这表明实验中的液滴生成具有很高的稳定性和可靠性。本研究不仅为微流控技术液滴生成的设计和实验提供了基础信息，也为ddPCR领域提供了一种可靠且高效的研究方法。
