Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany.
Adv Colloid Interface Sci. 2014 Jun;208:14-24. doi: 10.1016/j.cis.2014.02.008. Epub 2014 Feb 18.
Biomimetic membranes are fluid and can undergo two different elastic deformations, bending and stretching. The bending of a membrane is primarily governed by two elastic parameters: its spontaneous (or preferred) curvature m and its bending rigidity κ. These two parameters define an intrinsic tension scale, the spontaneous tension 2 κm². Membrane stretching and compression, on the other hand, are determined by the mechanical tension acting within the membrane. For vesicle membranes, the two elastic deformations are coupled via the enclosed vesicle volume even in the absence of mechanical forces as shown here by minimizing the combined bending and stretching energy with respect to membrane area for fixed vesicle volume. As a consequence, the mechanical tension within a vesicle membrane depends on the spontaneous curvature and on the bending rigidity. This interdependence, which is difficult to grasp intuitively, is then illustrated for a variety of simple vesicle shapes. Depending on the vesicle morphology, the magnitude of the mechanical tension can be comparable to or can be much smaller than the spontaneous tension.
仿生膜是流体的，可以发生两种不同的弹性变形，弯曲和拉伸。膜的弯曲主要由两个弹性参数决定：其自发（或优先）曲率 m 和弯曲刚度 κ。这两个参数定义了一个固有张力尺度，即自发张力 2 κm²。另一方面，膜的拉伸和压缩由膜内的机械张力决定。对于囊泡膜，即使在没有机械力的情况下，两个弹性变形也通过封闭的囊泡体积耦合，如这里所示，通过最小化弯曲和拉伸能量的总和来实现，膜面积固定，囊泡体积不变。因此，囊泡膜内的机械张力取决于自发曲率和弯曲刚度。这种直观上难以理解的相互依赖性，然后通过各种简单的囊泡形状来说明。根据囊泡的形态，机械张力的大小可以与自发张力相当，也可以比自发张力小得多。
