Lifetime and strength of periodic bond clusters between elastic media under inclined loading.
Lifetime and strength of periodic bond clusters between elastic media under inclined loading.
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DOI：
10.1016/j.bpj.2009.08.027
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发表时间：
2009-11
影响因子：
3.4
通讯作者：
J. Qian;Jizeng Wang;Yuan Lin;Huajian Gao
中科院分区：
文献类型：
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作者：
J. Qian;Jizeng Wang;Yuan Lin;Huajian Gao
粘着斑是将动物细胞与细胞外基质连接起来的特定受体-配体键簇。为了理解粘着斑的机械响应，我们在这里开发了一种随机弹性模型，该模型是在受到倾斜拉伸应力的两种不同弹性介质之间的粘着簇的周期性阵列上进行的，其中分子键的随机描述和界面牵引力的弹性描述统一在一个建模框架中。我们首先建立了界面牵引力分布的基本标度定律，并推导出了一个应力集中指数，该指数控制分子键内界面牵引力的均匀分布和裂纹状奇异分布之间的过渡。然后，在该比例定律的指导下，我们进行蒙特卡罗模拟，以研究簇大小、细胞/细胞外基质模量和加载方向对粘附簇的寿命和强度的影响。结果表明，中等粘附尺寸、刚性基底、细胞骨架硬化和小角度牵拉是有助于粘着斑稳定性的因素。我们的模型的预测为广泛的实验观察提供了可行的解释，并提出了细胞通过细胞骨架收缩机制调节粘附和死粘附并感知周围环境的机械特性的可能机制。
Focal adhesions are clusters of specific receptor-ligand bonds that link an animal cell to an extracellular matrix. To understand the mechanical responses of focal adhesions, here we develop a stochastic-elasticity model of a periodic array of adhesion clusters between two dissimilar elastic media subjected to an inclined tensile stress, in which stochastic descriptions of molecular bonds and elastic descriptions of interfacial traction are unified in a single modeling framework. We first establish a fundamental scaling law of interfacial traction distribution and derive a stress concentration index that governs the transition between uniform and cracklike singular distributions of the interfacial traction within molecular bonds. Guided by this scaling law, we then perform Monte Carlo simulations to investigate the effects of cluster size, cell/extracellular matrix modulus, and loading direction on lifetime and strength of the adhesion clusters. The results show that intermediate adhesion size, stiff substrate, cytoskeleton stiffening, and low-angle pulling are factors that contribute to the stability of focal adhesions. The predictions of our model provide feasible explanations for a wide range of experimental observations and suggest possible mechanisms by which cells can modulate adhesion and deadhesion via cytoskeletal contractile machinery and sense mechanical properties of their surroundings.