Lee Jihyeong, Lee Saebom, Lee Minki, Prakash Ritesh, Kim Hyejeong, Cho Gyoujin, Lee Jinkee
School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Korea.
Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Korea.
Micromachines (Basel). 2022 Jul 29;13(8):1218. doi: 10.3390/mi13081218.
Lab-on-a-CD (LOCD) is gaining importance as a diagnostic platform due to being low-cost, easy-to-use, and portable. During LOCD usage, mixing and reaction are two processes that play an essential role in biochemical applications such as point-of-care diagnosis. In this paper, we numerically and experimentally investigate the effects of the Coriolis and Euler forces in the mixing chamber during the acceleration and deceleration of a rotating disk. The mixing performance is investigated under various conditions that have not been reported, such as rotational condition, chamber aspect ratio at a constant volume, and obstacle arrangement in the chamber. During disk acceleration and deceleration, the Euler force difference in the radial direction causes rotating flows, while the Coriolis force induces perpendicular vortices. Increasing the maximum rotational velocity improves the maximum rotational displacement, resulting in better mixing performance. A longer rotational period increases the interfacial area between solutions and enhances mixing. Mixing performance also improves when there is a substantial difference between Euler forces at the inner and outer radii. Furthermore, adding obstacles in the angular direction also passively promotes or inhibits mixing by configuration. This quantitative investigation provides valuable information for designing and developing high throughput and multiplexed point-of-care LOCDs.
光盘实验室（LOCD）作为一种诊断平台正变得越来越重要，因为它成本低、易于使用且便于携带。在LOCD的使用过程中，混合和反应是生物化学应用（如即时诊断）中起关键作用的两个过程。在本文中，我们通过数值模拟和实验研究了旋转盘加速和减速过程中混合腔内科里奥利力和欧拉力的影响。在各种未被报道的条件下研究了混合性能，如旋转条件、恒定体积下的腔室纵横比以及腔内障碍物的排列。在盘加速和减速过程中，径向的欧拉力差会导致旋转流，而科里奥利力会诱导垂直涡旋。增加最大旋转速度可提高最大旋转位移，从而获得更好的混合性能。更长的旋转周期会增加溶液之间的界面面积并增强混合。当内半径和外半径处的欧拉力存在显著差异时，混合性能也会提高。此外，在角向添加障碍物也会通过其构型被动地促进或抑制混合。这项定量研究为设计和开发高通量和多重即时诊断LOCD提供了有价值的信息。
