Nonlinear viscoelasticity of adherent cells is controlled by cytoskeletal tension
Nonlinear viscoelasticity of adherent cells is controlled by cytoskeletal tension
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DOI：
10.1039/c0sm00833h
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发表时间：
2011-01-01
期刊：
影响因子：
3.4
通讯作者：
Fabry, Ben
中科院分区：
文献类型：
--
作者：
Kollmannsberger, Philip;Mierke, Claudia Tanja;Fabry, Ben
活细胞对微小外力和变形的粘弹性响应在时间上表现为弱幂规律。细胞的弹性模数和弹性应力衰减的幂指数依赖于细胞骨架中的主动收缩预应力。目前尚不清楚这是否也适用于大的外力和变形的生理相关制度。我们使用磁钳对绑定在不同细胞系细胞骨架上的磁珠施加逐步增加的力，并记录由此产生的细胞变形(蠕变反应)。在所有的力水平下，蠕变响应都遵循弱幂定律。所有细胞的硬度和幂指数随力的增加而增加，表明细胞骨架同时存在应力僵硬和流态化。不同细胞类型的应力硬化和流态化程度有很大差异，但以收缩预应力为唯一的自由参数。我们的结果表明，通过调节内部机械张力，细胞可以在非常大的范围内主动控制其机械性能。这一行为对于防止大的外力造成的损害具有根本的重要性，并使细胞能够适应细胞外基质高度可变和非线性的机械特性。
The viscoelastic response of living cells to small external forces and deformations is characterized by a weak power law in time. The elastic modulus of cells and the power law exponent with which the elastic stresses decay depend on the active contractile prestress in the cytoskeleton. It is unknown whether this also holds in the physiologically relevant regime of large external forces and deformations. We used magnetic tweezers to apply stepwise increasing forces to magnetic beads bound to the cytoskeleton of different cell lines, and recorded the resulting cell deformation (creep response). The creep response followed a weak power law at all force levels. Stiffness and power law exponent increased with force in all cells, indicating simultaneous stress stiffening and fluidization of the cytoskeleton. The amount of stress stiffening and fluidization differed greatly between cell types but scaled with the contractile prestress as the only free parameter. Our results demonstrate that by modulating the internal mechanical tension, cells can actively control their mechanical properties over an exceedingly large range. This behavior is of fundamental importance for protection against damage caused by large external forces, and allows the cells to adapt to the highly variable and nonlinear mechanical properties of the extracellular matrix.