The mechanics of animal cells is strongly determined by stress fibers, which are contractile filament bundles that form dynamically in response to extracellular cues. Stress fibers allow the cell to adapt its mechanics to environmental conditions and to protect it from structural damage. While the physical description of single stress fibers is well-developed, much less is known about their spatial distribution on the level of whole cells. Here, we combine a finite element method for one-dimensional fibers embedded in an elastic bulk medium with dynamical rules for stress fiber formation based on genetic algorithms. We postulate that their main goal is to achieve minimal mechanical stress in the bulk material with as few fibers as possible. The fiber positions and configurations resulting from this optimization task alone are in good agreement with those found in experiments where cells in 3D-scaffolds were mechanically strained at one attachment point. For optimized configurations, we find that stress fibers typically run through the cell in a diagonal fashion, similar to reinforcement strategies used for composite material.

中文翻译：

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应力纤维在收缩单元中的定位最大限度地减少了内部机械应力


动物细胞的机制在很大程度上取决于应力纤维，应力纤维是在细胞外线索下动态形成的收缩细丝束。应力纤维使电池能够使其机械结构适应环境条件并保护其免受结构损伤。虽然单应力纤维的物理描述已经很成熟，但对它们在整个细胞水平上的空间分布知之甚少。在这里，我们将嵌入弹性体介质中的一维纤维的有限元方法与基于遗传算法的应力纤维形成动力学规则相结合。我们假设他们的主要目标是用尽可能少的纤维在散装材料中实现最小的机械应力。仅由此优化任务得出的纤维位置和配置与实验中发现的非常一致，其中 3D 支架中的细胞在一个附着点处受到机械应变。对于优化配置，我们发现应力纤维通常以对角线方式穿过单元，类似于用于复合材料的增强策略。