Numerical investigations of the dynamics of two-component vesicles
Numerical investigations of the dynamics of two-component vesicles
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DOI：
10.1088/0953-8984/23/28/284103
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发表时间：
2011-07
期刊：
影响因子：
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通讯作者：
T. Taniguchi;M. Yanagisawa;M. Imai
中科院分区：
文献类型：
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作者：
T. Taniguchi;M. Yanagisawa;M. Imai
我们研究了双组分囊泡的变形和相分离的动力学。首先，我们数值研究了（i）热噪声，（ii）流体动力学流动引起的线张力的域边界和（iii）组成依赖的弯曲刚度上的粗化动力学的相分离图案的表面上的固定形状的囊泡的影响。发现相分离图案粗化的动力学指数z（NDB <$t-z，畴边界的总长度）从没有热噪声时的z = 1/3减小到包括热噪声影响时的1/5 < z < 1/4。我们还发现，流体动力学效应增强了球形囊泡在双连续相分离中的粗化。在相分离的形状固定的管状囊泡，带状相分离与周期性沿着长轴的管发生，因为组成依赖的弯曲刚度和较高的曲率在管端盖。其次，我们还探讨了形状变形与相分离的动力学，通过膜的弯曲刚度取决于脂质中的局部组合物，并发现组合物依赖的弯曲刚度至关重要地影响相分离和变形的囊泡。模拟的结果与实验观察到的称为“形状收敛”的行为（Yanagisawa等人2008 Phys. Rev. Lett. 100 148102）。
We examined the dynamics of the deformation and phase separation of two-component vesicles. First, we numerically investigated the effects of (i) thermal noise, (ii) hydrodynamic flow induced by the line tension of the domain boundary and (iii) composition-dependent bending rigidity on the coarsening dynamics of a phase-separated pattern on the surfaces of vesicles with fixed shapes. The dynamical exponent z (NDB ∼ t − z, the total length of the domain boundaries) of the coarsening of the phase-separated pattern was found to decrease from z = 1/3 under no thermal noise to 1/5 < z < 1/4 when including the effects of thermal noise. We also found that the hydrodynamic effect enhances the coarsening in a bicontinuous phase separation for a spherical vesicle. In phase separations of a shape-fixed tubular vesicle, a band-like phase separation with periodicity along the longer axis of the tube occurs because of the composition-dependent bending rigidity and the higher curvatures at the tube end-caps. Second, we also explored the dynamics of shape deformation coupled with phase separation through the bending rigidity of the membrane which depends on the local composition in lipids and found that the composition-dependent bending rigidity crucially influences the phase separation and deformation of the vesicle. The results of simulations are in good agreement with experimentally observed behavior known as ‘shape convergence’ (Yanagisawa et al 2008 Phys. Rev. Lett. 100 148102).