Yuan Hongyan, Huang Changjin, Li Ju, Lykotrafitis George, Zhang Sulin
Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Jul;82(1 Pt 1):011905. doi: 10.1103/PhysRevE.82.011905. Epub 2010 Jul 12.
Biological membranes are involved in numerous intriguing biophysical and biological cellular phenomena of different length scales, ranging from nanoscale raft formation, vesiculation, to microscale shape transformations. With extended length and time scales as compared to atomistic simulations, solvent-free coarse-grained membrane models have been exploited in mesoscopic membrane simulations. In this study, we present a one-particle-thick fluid membrane model, where each particle represents a cluster of lipid molecules. The model features an anisotropic interparticle pair potential with the interaction strength weighed by the relative particle orientations. With the anisotropic pair potential, particles can robustly self-assemble into fluid membranes with experimentally relevant bending rigidity. Despite its simple mathematical form, the model is highly tunable. Three potential parameters separately and effectively control diffusivity, bending rigidity, and spontaneous curvature of the model membrane. As demonstrated by selected examples, our model can naturally simulate dynamics of phase separation in multicomponent membranes and the topological change of fluid vesicles.
生物膜参与了许多不同长度尺度上有趣的生物物理和生物细胞现象，从纳米尺度的筏形成、囊泡化到微米尺度的形状转变。与原子模拟相比，由于具有更长的长度和时间尺度，无溶剂粗粒化膜模型已被用于介观膜模拟。在本研究中，我们提出了一种单粒子厚的流体膜模型，其中每个粒子代表一组脂质分子。该模型具有各向异性的粒子间对势，其相互作用强度由相对粒子取向加权。借助各向异性对势，粒子能够稳健地自组装成具有实验相关弯曲刚度的流体膜。尽管其数学形式简单，但该模型具有高度的可调性。三个势参数分别且有效地控制模型膜的扩散率、弯曲刚度和自发曲率。通过选定的示例表明，我们的模型能够自然地模拟多组分膜中相分离的动力学以及流体囊泡的拓扑变化。
