Dong Shoubin, Huang Zetao, Tang Liqun, Zhang Xiaoyang, Zhang Yongrou, Jiang Yi
a School of Computer Science & Engineering , South China University of Technology , Guangzhou , China.
b School of Civil Engineering & Transportation , South China University of Technology , Guangzhou , China.
Comput Methods Biomech Biomed Engin. 2017 Jul;20(9):991-1003. doi: 10.1080/10255842.2017.1321113. Epub 2017 Apr 26.
The extracellular matrix (ECM) provides structural and biochemical support to cells and tissues, which is a critical factor for modulating cell dynamic behavior and intercellular communication. In order to further understand the mechanisms of the interactive relationship between cell and the ECM, we developed a three-dimensional (3D) collagen-fiber network model to simulate the micro structure and mechanical behaviors of the ECM and studied the stress-strain relationship as well as the deformation of the ECM under tension. In the model, the collagen-fiber network consists of abundant random distributed collagen fibers and some crosslinks, in which each fiber is modeled as an elastic beam and a crosslink is modeled as a linear spring with tensile limit, it means crosslinks will fail while the tensile forces exceed the limit of spring. With the given parameters of the beam and the spring, the simulated tensile stress-strain relation of the ECM highly matches the experimental results including damaged and failed behaviors. Moreover, by applying the maximal inscribed sphere method, we measured the size distribution of pores in the fiber network and learned the variation of the distribution with deformation. We also defined the alignment of the collagen-fibers to depict the orientation of fibers in the ECM quantitatively. By the study of changes of the alignment and the damaged crosslinks against the tensile strain, this paper reveals the comprehensive mechanisms of four stages of 'toe', 'linear', 'damage' and 'failure' in the tensile stress-strain relation of the ECM which can provide further insight in the study of cell-ECM interaction.
细胞外基质（ECM）为细胞和组织提供结构和生化支持，这是调节细胞动态行为和细胞间通讯的关键因素。为了进一步了解细胞与ECM相互作用关系的机制，我们构建了一个三维（3D）胶原纤维网络模型来模拟ECM的微观结构和力学行为，并研究了其在拉伸下的应力应变关系以及变形情况。在该模型中，胶原纤维网络由大量随机分布的胶原纤维和一些交联点组成，其中每根纤维被建模为弹性梁，交联点被建模为具有拉伸极限的线性弹簧，这意味着当拉力超过弹簧极限时交联点会失效。通过给定梁和弹簧的参数，模拟得到的ECM拉伸应力应变关系与包括损伤和失效行为在内的实验结果高度匹配。此外，应用最大内接球法，我们测量了纤维网络中孔隙的尺寸分布，并了解了其随变形的分布变化。我们还定义了胶原纤维的排列来定量描述ECM中纤维的取向。通过研究排列和受损交联点随拉伸应变的变化，本文揭示了ECM拉伸应力应变关系中“趾部”“线性”“损伤”和“失效”四个阶段的综合机制，这可为细胞与ECM相互作用的研究提供进一步的见解。
