On the mechanical modeling of cell components
On the mechanical modeling of cell components
复制标题
细胞组件的力学建模
DOI：
10.1002/pamm.202000129
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
G. A. Holzapfel
中科院分区：
文献类型：
--
作者：
S. Klinge;T. Wiegold;S. Aygün;R. P. Gilbert;G. A. Holzapfel
真核细胞是执行各种不同任务的复杂系统。目前的报告深入了解了对其中一些重要组成部分进行建模的情况，并概述了在D-A-CH国际项目内对单间运输过程进行计算建模所取得的成果。论文的第一部分研究了包埋在胞浆中的交联型肌动蛋白网络的粘弹性效应。基本模型用于在微观水平上模拟肌动蛋白的行为。它考虑了物理长度、端到端距离和拉伸模数的影响，以提供单个聚合物链的伸长量与所施加的拉力之间的关系。用多尺度有限元方法模拟了细胞质的有效行为。在这里，标准的大应变粘性方法被应用于胞浆，而广义的Maxwell模型模拟了由于偏差变化而在细丝中发生的粘性效应。结合张力保持试验的例子让我们深入了解细胞质的有效行为。演讲的第二部分涉及由受体运动驱动的病毒进入细胞。在建立的模型中，受体的运动用扩散方程和两个边界条件来描述。第一个条件表示接触区前部的通量平衡。为此，假定速度与化学势的梯度成正比。第二个条件涉及能量平衡，并假定锋面前后的能量差异导致了锋面的运动。重要的能量贡献是受体结合所产生的能量、膜的自由能、弯曲能和受体运动所产生的动能。该模型产生了一个适定的移动边界问题，并用有限差分方法进行了数值求解。数值模拟研究了膜上受体密度的变化以及粘附区前沿的运动。
Eukaryotic cells are complex systems which carry out a variety of different tasks. The current contribution gives insight into the modeling of some of their vital components and represents an overview of results achieved within the international D‐A‐CH project on computational modeling of transport processes in a cell. The first part of the contribution studies viscoelastic effects of cross‐linked actin network embedded in cytosol. The basic‐model is used to simulate the actin behavior at a microscopic level. It considers the influence of the physical length, the end‐to‐end distance and the stretch modulus in order to provide a relationship between the stretch of a single polymer chain and the applied tension force. The effective behavior of the cell cytoplasm is simulated by using the multiscale finite element method. Here, a standard large strain viscous approach is applied for the cytosol, while the generalized Maxwell model simulates viscous effects occurring in filaments due to deviatoric changes. The examples dealing with combinations of tension‐holding tests give insight into the effective behavior of the cytoplasm.The second part of the talk deals with the viral entry into a cell driven by the receptor motion. In the model developed, the receptor motion is described by the diffusion equation along with two boundary conditions. The first condition represents the balance of fluxes at the front of the contact area. To this end, the velocity is assumed to be proportional to the gradient of the chemical potential. The second condition deals with the energy balance and postulates that the difference in the energy behind and before the front causes the front's movement. The important energy contributions are energy due to the binding of receptors, the free energy of the membrane, the bending energy and the kinetic energy due to the motion of the receptors. The model yields a well‐posed moving boundary problem, which is numerically solved using the finite difference method. The change of receptor density over the membrane as well as the motion of the front of the adhesion zone is studied in the numerical simulations.