Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut, USA.
Biophys J. 2012 Jan 4;102(1):75-84. doi: 10.1016/j.bpj.2011.11.4012. Epub 2012 Jan 3.
We present a two-component coarse-grained molecular-dynamics model for simulating the erythrocyte membrane. The proposed model possesses the key feature of combing the lipid bilayer and the erythrocyte cytoskeleton, thus showing both the fluidic behavior of the lipid bilayer and the elastic properties of the erythrocyte cytoskeleton. In this model, three types of coarse-grained particles are introduced to represent clusters of lipid molecules, actin junctions, and band-3 complexes, respectively. The proposed model facilitates simulations that span large length scales (approximately micrometers) and timescales (approximately milliseconds). By tuning the interaction potential parameters, we were able to control the diffusivity and bending rigidity of the membrane model. We studied the membrane under shearing and found that at a low shear strain rate, the developed shear stress was due mainly to the spectrin network, whereas the viscosity of the lipid bilayer contributed to the resulting shear stress at higher strain rates. In addition, we investigated the effects of a reduced spectrin network connectivity on the shear modulus of the membrane.
我们提出了一个两组件的粗粒化分子动力学模型来模拟红细胞膜。所提出的模型具有将脂质双层和红细胞细胞骨架结合的关键特征,从而显示出脂质双层的流态行为和红细胞细胞骨架的弹性性质。在这个模型中,引入了三种类型的粗粒化粒子来分别代表脂质分子簇、肌动蛋白连接和带 3 复合物。所提出的模型便于模拟跨越大长度尺度(约几微米)和时间尺度(约几毫秒)的过程。通过调整相互作用势能参数,我们能够控制膜模型的扩散率和弯曲刚性。我们研究了在剪切下的膜,发现当剪切应变速率较低时,所产生的剪切应力主要归因于血影蛋白网络,而在较高应变速率下,脂质双层的粘度对产生的剪切应力有贡献。此外,我们研究了减少血影蛋白网络连通性对膜剪切模量的影响。