Department of Physics, Tohoku University, Aoba, Sendai, 980-8578, Japan.
Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia.
Soft Matter. 2023 Jun 14;19(23):4286-4296. doi: 10.1039/d3sm00308f.
We investigate the morphologies of adhering vesicle triplets as a function of volume-to-area ratio encoded by the reduced volume in strong and weak adhesion regimes. In the strong adhesion regime, the morphology change of the vesicle triplet depends on the arrangement of vesicles. By decreasing the reduced volume, a triangular triplet composed of three spherical caps with a trifurcated flat contact zone deformed to a compact spherical shape with a sigmoidal contact zone, whereas a linear vesicle triplet composed of pancake-shaped vesicles sandwiched between two spherical-cap vesicles with a flat contact zone deformed into a compact spherical shape with biconvex interfaces. The morphologies of vesicle triplets with flat contact zones are reproduced by the so-called two-tension model based on the total energy consisting of bending energy, adhesion energy and surface energy, where the surface tension in the noncontact zone is different from that in the contact zone. When the flat interface deforms, the two-tension model is no longer applicable. The compact spherical triplets with curved interfaces can be reproduced by introducing geometrical constraints requiring that the total area of the non-contact zones is minimal, thereby confining the aggregate to a spherical cavity; this is referred to as the cavity model. In the weak adhesion regime, vesicle triplets with either a triangular or linear topology deform into prolate-based triplets by decreasing the reduced volume.
我们研究了附着的囊泡三聚体的形态作为由强和弱粘附区的体积-面积比编码的减少体积的函数。在强粘附区，囊泡三聚体的形态变化取决于囊泡的排列。通过减小减少的体积，由三个球形帽组成的三角形三聚体，具有三叉形平坦接触区，变形为具有折皱状接触区的紧密球形，而由两个球形帽之间夹着两个盘形囊泡组成的线性囊泡三聚体，具有平坦接触区，变形为具有双凸界面的紧密球形。具有平坦接触区的囊泡三聚体的形态通过基于由弯曲能、粘附能和表面能组成的总能量的所谓双张力模型再现，其中非接触区的表面张力与接触区的表面张力不同。当平坦界面变形时，双张力模型不再适用。通过引入要求非接触区的总面积最小的几何约束，可以再现具有弯曲界面的紧密球形三聚体，从而将聚集体限制在球形腔中；这被称为腔模型。在弱粘附区，通过减小减少的体积，具有三角形或线性拓扑的囊泡三聚体变形为基于长轴的三聚体。
