FluME, Department of Mechanical Engineering, University College London (UCL), London, WC1E 7JE, United Kingdom.
FluME, Department of Mechanical Engineering, University College London (UCL), London, WC1E 7JE, United Kingdom; Department of Mechanical Engineering and Material Science Engineering, Cyprus University of Technology, Limassol, Cyprus.
Med Eng Phys. 2022 Sep;107:103874. doi: 10.1016/j.medengphy.2022.103874. Epub 2022 Aug 10.
Red blood cell (RBC) deformability is an important haemorheological factor; it is impaired in many pathologies leading to microvascular complications. Several microfluidic platforms have been utilized to examine the role of deformability in RBC flows but their geometries tend to be simplified. In the present study, we extend our previous work on healthy RBC flows in micropillar arrays [1] to probe the effect of impaired RBC deformability on the velocity and haematocrit distributions in microscale RBC flows. Healthy and artificially hardened RBC suspensions at 25% haematocrit were perfused through the micropillar array at various flow rates and imaged. RBC velocities were determined by Particle Image Velocimetry (PIV) and haematocrit distributions were inferred from the image intensity distributions. The pillars divide the flow into two distinct RBC streams separated by a cell-depleted region along the centreline and in the rear/front stagnation points. RBC deformability was not found to significantly affect the velocity distributions; the shape of the velocity profiles in the interstitial space remained the same for healthy and hardened RBCs. Time-averaged and spatiotemporal intensity distributions, however, reveal differences in the dynamics and local distributions of healthy and hardened cells; hardened cells appear to enter the cell-depleted regions more frequently and their interstitial distributions are more uniform. The study highlights the importance of local RBC distributions and the impact of RBC deformability on cell transport in complex microscale flows.
红细胞（RBC）变形性是一个重要的血液流变学因素；它在许多导致微血管并发症的病理状态下受损。已经有几种微流控平台被用于研究变形性在 RBC 流动中的作用，但它们的几何形状往往被简化了。在本研究中，我们扩展了之前关于健康 RBC 在微柱阵列中流动的工作[1]，以探讨 RBC 变形性受损对微尺度 RBC 流动中速度和血细胞比容分布的影响。将 25%血细胞比容的健康和人工硬化 RBC 悬浮液以不同的流速灌注入微柱阵列，并进行成像。通过粒子图像测速（PIV）确定 RBC 速度，并从图像强度分布推断血细胞比容分布。微柱将流动分为两个不同的 RBC 流，在中心线和后/前停滞点处沿细胞耗尽区域分开。RBC 变形性并未显著影响速度分布；健康和硬化 RBC 的间质空间中的速度曲线形状相同。然而，时均和时空强度分布揭示了健康和硬化细胞的动力学和局部分布的差异；硬化细胞似乎更频繁地进入细胞耗尽区域，其间质分布更加均匀。该研究强调了局部 RBC 分布的重要性以及 RBC 变形性对复杂微尺度流动中细胞运输的影响。
