红细胞拉伸变形的粗粒化模拟

Coarse grained Simulation of Red Blood Cells Stretching Deformation

摘要:

采用最近提出的一种红细胞膜粗粒化网络模型研究红细胞在外力作用下的变形.该模型中细胞膜由非线性弹簧连接构成的网状结构组成，弹簧选用蠕虫链模型.系统的自由能考虑面内自由能、弯曲自由能、红细胞表面积和体积控制势能.经过粗粒化参数处理，利用耗散粒子动力学方法模拟红细胞在拉力作用下的变形.对模型中量纲一参数与真实物理量之间的对应关系进行讨论，对弯曲势能及面积、体积控制势能所对应的粒子点上的受力进行分析，并验证前人的计算与实验结果.结果表明:红细胞膜粗粒化网络模型能有效地模拟红细胞的变形，但红细胞的变形受多种因素影响，需要不断完善模型.

Abstract:

To study the deformation of red blood cells (RBCs) acted upon by an external force, a coarse grained network model of RBCs’ membrane presented recently was adopted. In the model, the membrane was constructed by a network of nonlinear springs, and the wormlike chain (WLC) spring model was applied. The free energy of the system took the in plane free energy, bending energy, area and volume conservation constraints into consideration. The RBCs model was handled by a systematic coarse graining procedure, and the coarse grained model was applied to simulating the stretching deformation of RBCs by using dissipative particle dynamics(DPD). The scaling procedure relating the model’s non dimensional units to physical units was discussed in detail, and the force acting on the vertices due to bend energy, area and volume conservation constraints were analyzed. The simulating results were compared with the experiments results. The results show that the coarse grained model is efficient in simulating the deformation of RBCs, but the model is influenced by many parameters, and it needs a further improving.