Mechanics of biomacromolecular networks containing folded domains
Mechanics of biomacromolecular networks containing folded domains
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DOI：
10.1115/1.2345442
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发表时间：
2006-10-01
影响因子：
1.2
通讯作者：
Boyce, Mary C.
中科院分区：
文献类型：
--
作者：
Qi, H. Jerry;Ortiz, Christine;Boyce, Mary C.
已知单个模块化生物大分子的力-延伸行为表现出一种特征性的重复模式，即力随着施加的位移而非线性上升到峰值，随后在达到峰值时显著的力下降。这种“锯齿”模式是拉伸诱导的模块沿着分子链展开的结果，并且被推测在生物材料和结构的功能中起支配作用。本文直接从基于统计力学的单分子力-伸展行为模型出发，建立了模块化大分子网络大应变变形的本构模型。所提出的二维网络模型具有适用性，生物膜骨架和三维网络模型模拟细胞骨架网络，天然纤维，和软生物组织。这些网络的单轴和多轴应力-应变行为的模拟说明了宏观膜和固体拉伸条件，激活这些微观结构中的展开。该模型同时跟踪在不同的宏观拉伸条件下，包括分子取向的演变和组成分子链和结上的力的演变的基本微观结构特征。给出了网络预张力对应力-应变行为的影响，以及引发网络展开的宏观应力和应变条件。各种生物材料的预测应力-应变行为的影响进行了讨论。
The force-extension behavior of single modular biomacromolecules is known to exhibit a characteristic repeating pattern of a nonlinear rise in force with imposed displacement to a peak, followed by a significant force drop upon reaching the peak. This "saw-tooth" pattern is a result of stretch-induced unfolding of modules along the molecular chain and is speculated to play a governing role in the function of biological materials and structures. In this paper constitutive models for the large strain deformation of networks of modular macromolecules are developed building directly from statistical mechanics based models of the single molecule force-extension behavior. The proposed two-dimensional network model has applicability, to biological membrane skeletons and the three-dimensional network model emulates cytoskeletal networks, natural fibers, and soft biological tissues. Simulations of the uniaxial and multiaxial stress-strain behavior of these networks illustrate the macroscopic membrane and solid stretching conditions which activate unfolding in these microstructures. The models simultaneously track the evolution in underlying microstructural features with different macroscopic stretching conditions, including the evolution in molecular orientation and the forces acting on the constituent molecular chains and junctions. The effect of network pretension on the stress-strain behavior and the macroscopic stress and strain conditions which trigger unfolding are presented. The implications of the predicted stress-strain behaviors on a variety of biological materials are discussed.