BioQuant and Institute of Theoretical Physics, Heidelberg University, Heidelberg, Germany.
Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany.
Soft Matter. 2019 Jul 10;15(27):5511-5520. doi: 10.1039/c9sm00677j.
Red blood cells in shear flow show a variety of different shapes due to the complex interplay between hydrodynamics and membrane elasticity. Malaria-infected red blood cells become generally adhesive and less deformable. Adhesion to a substrate leads to a reduction in shape variability and to a flipping motion of the non-spherical shapes during the mid-stage of infection. Here, we present a complete state diagram for wall adhesion of red blood cells in shear flow obtained by simulations, using a particle-based mesoscale hydrodynamics approach, multiparticle collision dynamics. We find that cell flipping at a substrate is replaced by crawling beyond a critical shear rate, which increases with both membrane stiffness and viscosity contrast between the cytosol and suspending medium. This change in cell dynamics resembles the transition between tumbling and tank-treading for red blood cells in free shear flow. In the context of malaria infections, the flipping-crawling transition would strongly increase the adhesive interactions with the vascular endothelium, but might be suppressed by the combined effect of increased elasticity and viscosity contrast.
在切变流中，由于水动力和膜弹性之间的复杂相互作用，红细胞呈现出多种不同的形状。感染疟疾的红细胞通常会变得更具黏附性，变形能力降低。与基底的黏附会导致形状变化的减少，并在感染中期导致非球形形状的翻转运动。在这里，我们通过使用基于粒子的介观水动力方法——多粒子碰撞动力学模拟，呈现了在切变流中红细胞壁黏附的完整状态图。我们发现，在基底上的细胞翻转被爬行所取代，当剪切率超过一个临界值时，这种爬行就会发生，而这个临界值会随着细胞膜的刚性和胞质与悬浮介质之间的粘性对比的增加而增加。这种细胞动力学的变化类似于在自由切变流中红细胞的翻滚和坦克履带式运动之间的转变。在疟疾感染的情况下，翻转-爬行的转变会强烈增加与血管内皮的黏附相互作用，但可能会被弹性和粘性对比增加的综合效应所抑制。
