Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
Acta Biomater. 2011 Jun;7(6):2374-83. doi: 10.1016/j.actbio.2011.02.026. Epub 2011 Feb 20.
We describe the mechanical behavior of isotropic fibrin networks at the macroscopic scale in terms of the nanoscale force response of fibrin molecules that are its basic building blocks. We show that the remarkable extensibility and compressibility of fibrin networks have their origins in the unfolding of fibrin molecules. The force-stretch behavior of a single fibrin fiber is described using a two-state model in which the fiber has a linear force-stretch relation in the folded phase and behaves like a worm-like-chain in the unfolded phase. The nanoscale force-stretch response is connected to the macro-scale stress-stretch response by means of the eight-chain model. This model is able to capture the macroscopic response of a fibrin network in uniaxial tension and appears remarkably simple given the molecular complexity. We use the eight-chain model to explain why fibrin networks have negative compressibility and Poisson's ratio greater than 1 due to unfolding of fibrin molecules.
我们根据构成其基本结构的纤维蛋白分子的纳米级力响应，来描述各向同性纤维蛋白网络在宏观尺度上的力学行为。我们表明，纤维蛋白网络的显著可扩展性和可压缩性源于纤维蛋白分子的展开。通过使用两状态模型来描述单根纤维蛋白纤维的力-拉伸行为，其中纤维在折叠相中具有线性力-拉伸关系，而在展开相中表现为类似蠕虫链的行为。纳米级力-拉伸响应通过八链模型与宏观尺度的应力-拉伸响应相关联。该模型能够捕捉纤维蛋白网络在单轴拉伸下的宏观响应，并且考虑到其分子复杂性，它看起来非常简单。我们使用八链模型来解释为什么纤维蛋白网络由于纤维蛋白分子的展开而具有负压缩性和泊松比大于 1。
