Stomatocyte-discocyte-echinocyte (SDE) transformations in human red blood cells (RBCs) have significant influences on blood dynamics and related disorders. The mechanical properties of the RBC membrane, such as shear modulus and bending elasticity, play crucial roles in determining RBC shapes. Recent biophysical findings reveal that building a comprehensive model capable of describing SDE shape transformations is a challenging problem. Based on dissipative particle dynamics, this study develops a two-component RBC model considering the detachment between the lipid bilayer and cytoskeleton, as well as the cytoskeletal reorganization during echinocyte formation. This model is validated by comparing RBCs’ geometric shape and the apparent membrane tension with previous experimental measurements. Results indicate that a complete SDE sequence represented by six typical shapes can be obtained by modulating the model’s mechanical and geometric parameters. Furthermore, a phase diagram based on reduced variables is obtained using principal-component analysis, demonstrating the phase transformations among SDE shapes. Our result suggests that the transformation from discocyte to stomatocyte is primarily influenced by dimensionless bending rigidity, whereas, during echinocyte formation, three key variables, i.e., dimensionless bending rigidity, targeting cytoskeleton shrinkage ratio, and connecting pattern, have joint impacts on the formation of spicules or bumps and the development of the cytoskeletal framework. The present two-component RBC model and the associated findings provide a perspective for a deeper understanding of the SDE transformation mechanism. This framework offers new insights into biological science and potential applications in the field of biomedical engineering.

中文翻译：

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受膜-细胞骨架力学特性调节的红细胞的口细胞-盘细胞-棘皮细胞转化


人红细胞 （RBC） 中的口细胞-盘细胞-棘细胞 （SDE） 转化对血液动力学和相关疾病有显着影响。RBC 膜的机械性能，例如剪切模量和弯曲弹性，在决定 RBC 形状方面起着至关重要的作用。最近的生物物理学发现表明，构建能够描述 SDE 形状变换的综合模型是一个具有挑战性的问题。基于耗散粒子动力学，本研究开发了一种双组分 RBC 模型，考虑了脂质双层和细胞骨架之间的分离，以及棘皮细胞形成过程中的细胞骨架重组。通过将 RBC 的几何形状和表观膜张力与以前的实验测量值进行比较来验证该模型。结果表明，通过调制模型的机械和几何参数，可以获得由六种典型形状表示的完整 SDE 序列。此外，使用主成分分析获得了基于约化变量的相图，展示了 SDE 形状之间的相变。我们的结果表明，从盘状细胞到口状细胞的转变主要受无量纲弯曲刚度的影响，而在棘细胞形成过程中，无量纲弯曲刚度、靶向细胞骨架收缩率和连接模式这三个关键变量对针状或凸起的形成和细胞骨架的发育有共同影响。目前的双组分 RBC 模型和相关发现为更深入地理解 SDE 转化机制提供了一个视角。该框架为生物科学和生物医学工程领域的潜在应用提供了新的见解。