College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China.
J Phys Condens Matter. 2011 Jul 20;23(28):285103. doi: 10.1088/0953-8984/23/28/285103. Epub 2011 Jun 28.
We investigate double-walled vesicles as a simple model system for multi-vesicular structures, where the inner membrane is confined within the outer membrane. Various shapes of double-walled vesicles in two dimensions are obtained by means of our recently-developed discrete space variation method, and the shapes of each layer are found to be interdependent. Confined within the outer membrane, an inner membrane with a larger surface area always shows a cristae shape. As previous simulations and theoretical analyses of a single-walled vesicle have been done before, the geometric properties of double-walled vesicles, including the mean square radius of gyration and volume within the vesicle membrane, are studied in detail as functions of the pressure and surface area. It is found that due to the inter-space restriction of each layer, double-walled vesicles exhibit different behaviors compared with the previously-observed scaling laws of single-walled vesicles. It is straightforward to extend this study to more complicated and realistic biological systems, such as those including electrostatic interactions between membranes and solvent, phase separation, and cooperative interactions between multicomponent membranes.
我们研究了双层囊泡作为多泡囊结构的简单模型系统，其中内层膜被限制在外层膜内。通过我们最近开发的离散空间变化方法，可以得到二维双层囊泡的各种形状，并且发现每个层的形状是相互依存的。在内层膜被限制在外层膜内的情况下，表面积较大的内层膜总是呈现出嵴状。由于之前已经对单层囊泡进行了模拟和理论分析，因此详细研究了双层囊泡的几何性质，包括囊泡膜内的均方回转半径和体积，作为压力和表面积的函数。结果发现，由于每层之间的空间限制，与之前观察到的单层囊泡的标度定律相比，双层囊泡表现出不同的行为。可以很容易地将这项研究扩展到更复杂和现实的生物系统，例如包括膜与溶剂之间的静电相互作用、相分离和多组分膜之间的协同相互作用。
