Simulation Files from Red blood cell dynamics in extravascular biological tissues modelled as canonical disordered porous media

The dynamics of blood flow in the smallest vessels and passages of the human body, where the cellular character of blood becomes prominent, plays a dominant role in the transport and exchange of solutes. Recent studies have revealed that the micro-haemodynamics of a vascular network is underpinned by its interconnected structure, and certain structural alterations such as capillary dilation and blockage can substantially change blood flow patterns. However, for extravascular media with disordered microstructure (e.g. the porous intervillous space in the placenta), it remains unclear how the medium’s structure affects the haemodynamics. Here, we simulate cellular blood flow in simple models of canonical porous media representative of extravascular biological tissue, with corroborative microfluidic experiments performed for validation purposes. For the media considered here, we observe three main effects: first, the relative apparent viscosity of blood increases with the structural disorder of the medium; second, the presence of red blood cells (RBCs) dynamically alters the flow distribution in the medium; third, symmetry breaking introduced by moderate structural disorder can promote more homogeneous distribution of RBCs. Our findings contribute to a better understanding of the cell-scale haemodynamics that mediates the relationship linking the function of certain biological tissues to their microstructure.

人体最小血管和腔隙中血流动力学的动态变化，其中血液的细胞特性尤为显著，在溶质的运输和交换过程中起着主导作用。近期研究揭示了血管网络的微血流动力学由其相互连接的结构所支撑，且某些结构改变，如毛细血管扩张和阻塞，会显著改变血流模式。然而，对于具有无序微结构的血管外介质（例如胎盘的孔隙绒毛间隙），介质的结构如何影响血流动力学尚不明确。在本研究中，我们通过简单的典型多孔介质模型模拟细胞血流，并进行了相应的微流控实验以验证其准确性。对于所考虑的介质，我们观察到三种主要效应：首先，血液的相对表观粘度随着介质结构的无序程度增加而增加；其次，红细胞（RBCs）的存在动态地改变了介质中的流动分布；第三，由适度的结构无序引入的对称性破坏可以促进红细胞的更均匀分布。我们的发现有助于更深入地理解细胞尺度上的血流动力学，该动力学中介了特定生物组织功能与其微结构之间的关系。