Division of Bioengineering, Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho Toyonaka, Osaka 560-8531, Japan.
Ann Biomed Eng. 2010 Apr;38(4):1530-8. doi: 10.1007/s10439-010-9930-8. Epub 2010 Jan 28.
We developed a mechano-cell model incorporating a cell membrane, a nuclear envelope, and actin filaments to simulate the mechanical behavior of a cell during tensile tests. The computational model depicts a cell as a combination of various spring elements in the framework of the minimum energy concept. A cell membrane and a nuclear envelope are both modeled as shells of a spring network that express elastic resistance to changes in bending, stretching, and surface area. A bundle of actin filaments is represented by a mechanical spring that generates a force as a function of its extension. The interaction between the nuclear envelope and the cell membrane is expressed by a potential energy function with respect to the distance between them. Incompressibility of a cell is assured by a volume elastic energy function. The cell shape during a tensile test is determined by a quasi-static approach, such that the total elastic energy converges to the minimum. The load-deformation curve obtained from the simulation shows a significant increase in stretching load with deformation of the cell and lies within a range of experimentally obtained load-deformation curves. The total elastic energy is dominated by the energy stored in the actin fibers. Actin fibers that are randomly oriented before loading tend to become aligned, passively, in the stretched direction. These results attribute the non-linearity in the load-deformation curve to passive reorientation of actin fibers in the stretched direction.
我们开发了一种机械细胞模型，其中包含细胞膜、核膜和肌动蛋白丝，以模拟细胞在拉伸试验过程中的力学行为。该计算模型将细胞描绘为基于最小能量概念的各种弹簧元件的组合。细胞膜和核膜都被建模为弹簧网络的壳，对弯曲、拉伸和表面积变化表现出弹性阻力。一束肌动蛋白丝由一个机械弹簧表示，该弹簧根据其延伸产生力。核膜和细胞膜之间的相互作用通过它们之间的距离的势能函数来表示。细胞的不可压缩性由体积弹性能量函数保证。在拉伸试验过程中，细胞的形状由准静态方法确定，使得总弹性能量收敛到最小值。从模拟中获得的载荷-变形曲线显示，随着细胞变形，拉伸载荷显著增加，并处于实验获得的载荷-变形曲线范围内。总弹性能量主要由肌动蛋白纤维中存储的能量主导。在加载前随机取向的肌动蛋白纤维在拉伸方向上趋于被动对齐。这些结果将载荷-变形曲线的非线性归因于拉伸方向上肌动蛋白纤维的被动重定向。
