Sahu Ajit Kumar, Malik Rajkumar, Midya Jiarul
Department of Physics, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Jatni, Odisha-752050, India.
Soft Matter. 2025 May 28;21(21):4275-4287. doi: 10.1039/d5sm00150a.
The wrapping of particles and vesicles by lipid bilayer membranes is a fundamental process in cellular transport and targeted drug delivery. Here, we investigate the wrapping behavior of nonspherical vesicles, such as ellipsoidal, prolate, oblate, and stomatocytes, by systematically varying the bending rigidity of the vesicle membrane and the tension of the initially planar membrane. Using the Helfrich Hamiltonian, triangulated membrane models, and energy minimization techniques, we predict multiple stable-wrapped states and identify the conditions for their coexistence. Our results demonstrate that softer vesicles bind more easily to initially planar membranes; however, complete wrapping requires significantly higher adhesion strength than rigid vesicles. As membrane tension increases, deep-wrapped states disappear at a triple point where shallow-wrapped, deep-wrapped, and complete-wrapped states coexist. The coordinates of the triple point are highly sensitive to the vesicle shape and stiffness. For stomatocytes, increasing stiffness shifts the triple point to higher adhesion strengths and membrane tensions, while for oblates, it shifts to lower values, influenced by shape changes during wrapping. Oblate shapes are preferred in shallow-wrapped states and stomatocytes in deep-wrapped states. In contrast to hard particles, where optimal adhesion strength for complete wrapping occurs at tensionless membranes, complete wrapping of soft vesicles requires finite membrane tension for optimal adhesion strength. These findings provide insights into the interplay between vesicle deformability, shape, and membrane properties, advancing our understanding of endocytosis and the design of advanced biomimetic delivery systems.
脂质双层膜对颗粒和囊泡的包裹是细胞运输和靶向药物递送中的一个基本过程。在此，我们通过系统地改变囊泡膜的弯曲刚度和初始平面膜的张力，研究了非球形囊泡（如椭球形、长形、扁形和口形细胞囊泡）的包裹行为。使用赫尔弗里希哈密顿量、三角化膜模型和能量最小化技术，我们预测了多个稳定的包裹状态，并确定了它们共存的条件。我们的结果表明，较软的囊泡更容易与初始平面膜结合；然而，与刚性囊泡相比，完全包裹需要显著更高的粘附强度。随着膜张力的增加，深度包裹状态在一个三相点消失，在该三相点处浅包裹、深度包裹和完全包裹状态共存。三相点的坐标对囊泡形状和刚度高度敏感。对于口形细胞囊泡，刚度增加会使三相点向更高的粘附强度和膜张力移动，而对于扁形囊泡，受包裹过程中形状变化的影响，三相点会向更低的值移动。浅包裹状态下扁形形状更受青睐，深度包裹状态下口形细胞囊泡更受青睐。与硬颗粒不同，硬颗粒在无张力膜处出现完全包裹的最佳粘附强度，而软囊泡的完全包裹需要有限的膜张力来达到最佳粘附强度。这些发现为囊泡变形性、形状和膜性质之间的相互作用提供了见解，推进了我们对胞吞作用和先进仿生递送系统设计的理解。
