A long-standing puzzle in the rheology of living cells is the origin of the experimentally observed long-time stress relaxation. The mechanics of the cell is largely dictated by the cytoskeleton, which is a biopolymer network consisting of transient crosslinkers, allowing for stress relaxation over time. Moreover, these networks are internally stressed due to the presence of molecular motors. In this work we propose a theoretical model that uses a mode-dependent mobility to describe the stress relaxation of such prestressed transient networks. Our theoretical predictions agree favorably with experimental data of reconstituted cytoskeletal networks and may provide an explanation for the slow stress relaxation observed in cells.

中文翻译：

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瞬态交联生物聚合物网络的非线性应力松弛

活细胞流变学中一个长期存在的难题是实验观察到的长期应力松弛的起源。细胞的力学主要由细胞骨架决定，细胞骨架是一种由瞬态交联剂组成的生物聚合物网络，可以随着时间的推移应力松弛。此外，由于分子马达的存在，这些网络在内部受到压力。在这项工作中，我们提出了一个理论模型，该模型使用依赖于模式的迁移率来描述这种预应力瞬态网络的应力松弛。我们的理论预测与重构细胞骨架网络的实验数据一致，并可能为细胞中观察到的缓慢应力松弛提供解释。