Assembly of type I collagen: fusion of fibril subunits and the influence of fibril diameter on mechanical properties
Assembly of type I collagen: fusion of fibril subunits and the influence of fibril diameter on mechanical properties
复制标题
DOI：
10.1016/s0945-053x(00)00089-5
复制
发表时间：
2000-09-01
期刊：
影响因子：
6.9
通讯作者：
Silver, FH
中科院分区：
文献类型：
--
作者：
Christiansen, DL;Huang, EK;Silver, FH
细胞外基质的结构稳定性主要是纤维性胶原蛋白和交联程度的结果。胶原蛋白自组装、纤维形状和力学性能之间的关系尚不清楚。我们的实验室开发了一个模型系统，用于制备具有纤维亚结构模拟肌腱分层结构的自组装I型胶原纤维。本研究评估了自组装过程中pH和温度对纤维结构的影响，并探讨了这些处理对自组装胶原纤维单轴拉伸力学性能的结构影响。对不同培养条件下形成的纤维的纤维直径分布和力学性能的分析结果表明，纤维直径是通过类似于4 nm的离散亚基的横向融合生长的，纤维直径与低应变模量呈正相关。纤维直径与极限抗拉强度和高应变弹性模量均不相关，这表明在小应变力学变形过程中，纤维的横向聚集和直径影响力学性能。我们假设自组装是由纤维亚基的形成介导的，这些纤维亚基横向和线性融合导致纤维生长。横向融合在低应变下产生抗变形能力方面起重要作用，而导致更长的原纤维的线性融合在高应变下的最终力学性能方面起重要作用。(C) 2000 Elsevier Science B.V./国际基质生物学学会。版权所有。
Structural stability of the extracellular matrix is primarily a consequence of fibrillar collagen and the extent of cross-linking. The relationship between collagen self-assembly, consequent fibrillar shape and mechanical properties remains unclear. Our laboratory developed a model system for the preparation of self-assembled type I collagen fibers with fibrillar substructure mimicking the hierarchical structures of tendon. The present study evaluates the effects of pH and temperature during self-assembly on fibrillar structure, and relates the structural effects of these treatments on the uniaxial tensile mechanical properties of self-assembled collagen fibers. Results of the analysis of fibril diameter distributions and mechanical properties of the fibers formed under the different incubation conditions indicate that fibril diameters grow via the lateral fusion of discrete similar to 4 nm subunits, and that fibril diameter correlates positively with the low strain modulus. Fibril diameter did not correlate with either the ultimate tensile strength or the high strain elastic modulus, which suggests that lateral aggregation and consequently fibril diameter influences mechanical properties during small strain mechanical deformation. We hypothesize that self-assembly is mediated by the formation of fibrillar subunits that laterally and linearly fuse resulting in fibrillar growth. Lateral fusion appears important in generating resistance to deformation at low strain, while linear fusion leading to longer fibrils appears important in the ultimate mechanical properties at high strain. (C) 2000 Elsevier Science B.V./International Society of Matrix Biology. All rights reserved.