Department of Bioinformatics and Life Science, Soongsil University, Seoul 06978, South Korea.
Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
J Chem Phys. 2023 Jul 14;159(2). doi: 10.1063/5.0148096.
We study the hydrodynamic coupling of neighboring micro-beads placed in a multiple optical trap setup allowing us to precisely control the degree of coupling and directly measure time-dependent trajectories of entrained beads. We performed measurements on configurations with increasing complexity starting with a pair of entrained beads moving in one dimension, then in two dimensions, and finally a triplet of beads moving in two dimensions. The average experimental trajectories of a probe bead compare well with the theoretical computation, illustrating the role of viscous coupling and setting timescales for probe bead relaxation. The findings also provide direct experimental corroborations of hydrodynamic coupling at large, micrometer spatial scales and long, millisecond timescales, of relevance to, e.g., microfluidic device design and hydrodynamic-assisted colloidal assembly, improving the capability of optical tweezers, and understanding the coupling between micrometer-scale objects within a living cell.
我们研究了放置在多光学陷阱设置中的相邻微珠的流体动力耦合，这使我们能够精确控制耦合程度，并直接测量被捕获微珠的时变轨迹。我们从一对在一维空间中运动的被捕获微珠开始，然后在二维空间中，最后是在二维空间中运动的三个微珠，对越来越复杂的配置进行了测量。探针微珠的平均实验轨迹与理论计算吻合较好，说明了粘性耦合的作用，并为探针微珠的弛豫设置了时间尺度。这些发现还为在大的、微米级空间尺度和长的、毫秒级时间尺度上的流体动力耦合提供了直接的实验佐证，这与微流控器件设计和流体力学辅助胶体组装等有关，提高了光学镊子的能力，并有助于理解活细胞内微米级物体之间的耦合。
