Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, 600036, India.
Department of Mechanical Engineering, Indian Institute of Science, Bangalore, 560012, India.
Int J Numer Method Biomed Eng. 2018 Sep;34(9):e3105. doi: 10.1002/cnm.3105. Epub 2018 Jun 25.
Understanding the dynamics of red blood cell (RBC) motion under in silico conditions is central to the development of cost-effective diagnostic tools. Specifically, unraveling the relationship between the rheological properties and the nature of shape change in the RBC (healthy or infected) can be extremely useful. In case of malarial infection, RBC progressively loses its deformability and tends to occlude the microvessel. In the present study, detailed mesoscopic simulations are performed to investigate the deformation dynamics of an RBC in flow through a constricted channel. Specifically, the manifestation of viscous forces (through flow rates) on the passage and blockage characteristics of a healthy red blood cell (hRBC) vis-á-vis an infected red blood cell (iRBC) are investigated. A finite-sized dissipative particle dynamics framework is used to model plasma in conjunction with a discrete model for the RBC. Instantaneous wall boundary method was used to model no-slip wall boundary conditions with a good control on the near-wall density fluctuations and compressibility effects. To investigate the microvascular occlusion, the RBC motion through 2 types of constricted channels, viz, (1) a tapered microchannel and (2) a stenosed-type microchannel, were simulated. It was observed that the deformation of an infected cell was much less compared with a healthy cell, with an attendant increase in the passage time. Apart from the qualitative features, deformation indices were obtained. The deformation of hRBC was sudden, while the iRBC deformed slowly as it traversed through the constriction. For higher flow rates, both hRBC and iRBC were found to undergo severe deformation. Even under low flow rates, hRBC could easily traverse past the constricted channel. However, for sufficiently slow flow rates (eg, capillary flows), the microchannel was found to be completely blocked by the iRBC.
理解红细胞（RBC）在计算条件下的运动动态对于开发具有成本效益的诊断工具至关重要。具体来说，揭示 RBC（健康或感染）的流变特性与形状变化性质之间的关系非常有用。在疟疾感染的情况下，RBC 的变形能力逐渐丧失，并且倾向于阻塞微血管。在本研究中，进行了详细的介观模拟，以研究 RBC 在受限通道中流动时的变形动力学。具体来说，研究了粘性力（通过流速）对健康红细胞（hRBC）和感染红细胞（iRBC）的通过和阻塞特性的影响。使用有限尺寸耗散粒子动力学框架来模拟血浆，同时使用 RBC 的离散模型。瞬时壁边界方法用于模拟无滑移壁边界条件，对近壁密度波动和可压缩性效应有很好的控制。为了研究微血管阻塞，模拟了 RBC 通过两种类型的受限通道的运动，即（1）锥形微通道和（2）狭窄型微通道。观察到感染细胞的变形比健康细胞小得多，同时通过时间增加。除了定性特征外，还获得了变形指数。hRBC 的变形是突然的，而 iRBC 在穿过收缩时变形缓慢。对于较高的流速，hRBC 和 iRBC 都被发现发生严重变形。即使在较低的流速下，hRBC 也可以轻易地穿过受限通道。然而，对于足够低的流速（例如，毛细血管流动），发现 iRBC 完全阻塞了微通道。
