Collective spreading of red blood cells flowing in a microchannel

Abstract

Due to recent advances in micro total analysis system technologies, microfluidics provides increased opportunities to manipulate, stimulate, and diagnose blood cells. Controlling the concentration of cells at a given position across the width of a channel is an important aspect in the design of microfluidic devices. Despite its biomedical importance, the collective spreading of red blood cells (RBCs) in a microchannel has not yet been fully clarified. In this study, we experimentally investigated the collective spreading of RBCs in a straight microchannel, and found that RBCs initially distributed in one side of the microchannel spread to the spanwise direction during downstream flow. Spreading increased considerably as the hematocrit increased, though the flow rate had a small effect. We proposed a scaling argument to show that this spreading phenomenon was diffusive and mainly induced by cell-cell interactions. The dispersion coefficient was approximately proportional to the flow rate and the hematocrit. These results are useful in understanding collective behaviors of RBCs in a microchannel and in microcirculation.由于微全分析系统技术的最新进展，微流控技术为操纵，刺激和诊断血细胞提供了更多的机会。在微流装置的设计中，控制通道宽度上给定位置的细胞浓度是重要的方面。尽管具有生物医学重要性，但尚未完全弄清红细胞（RBC）在微通道中的集体扩散。在这项研究中，我们通过实验研究了RBC在直的微通道中的集体扩散，并发现RBC最初分布在微通道的一侧，在下游流动过程中向翼展方向扩散。尽管流量影响很小，但随着血细胞比容的增加，传播也大大增加。我们提出了一个比例论证来表明这种扩散现象是扩散性的，并且主要是由细胞间相互作用引起的。分散系数与流量和血细胞比容大致成正比。这些结果有助于理解RBC在微通道和微循环中的集体行为。