Bose Shirsha, Li Simin, Mele Elisa, Silberschmidt Vadim V
Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
Department of Materials, Loughborough University, Loughborough, Leicestershire, LE113TU, UK.
J Mech Behav Biomed Mater. 2020 Nov;111:103983. doi: 10.1016/j.jmbbm.2020.103983. Epub 2020 Aug 6.
Collagen forms one-third of the body proteome and has emerged as an important biomaterial for tissue engineering and wound healing. Collagen films are used in tissue regeneration, wound treatment, dural substitute etc. as well as in flexible electronics. Thus, the mechanical behaviour of collagen should be studied under different environmental conditions and strain rates relevant for potential applications. This study's aim is to assess the mechanical behaviour of collagen films under different environmental conditions (hydration, submersion and physiological temperature (37 °C)) and strain rates. The combination of all three environment factors (hydration, submersion and physiological temperature (37 °C)) resulted in a drop of tensile strength of the collagen film by some 90% compared to that of dry samples, while the strain at failure increased to about 145%. For the first time, collagen films were subjected to different strain rates ranging from quasi-static (0.0001 s) to intermediate (0.001 s, 0.01 s) to dynamic (0.1 s, 1 s) conditions, with the strain-rate-sensitivity exponent (m) reported. It was found that collagen exhibited a strain-rate-sensitive hardening behaviour with increasing strain rate. The exponent m ranged from 0.02-0.2, with a tendency to approach zero at intermediate strain rate (0.01 s), indicating that collagen may be strain-rate insensitive in this regime. From the identification of hyperelastic parameter of collagen film, it was found that the Ogden Model provides realistic results for future simulations.
胶原蛋白占人体蛋白质组的三分之一，已成为组织工程和伤口愈合的重要生物材料。胶原膜用于组织再生、伤口治疗、硬脑膜替代物等以及柔性电子学。因此，应在与潜在应用相关的不同环境条件和应变率下研究胶原蛋白的力学行为。本研究的目的是评估胶原膜在不同环境条件（水合、浸没和生理温度（37°C））和应变率下的力学行为。与干燥样品相比，所有三个环境因素（水合、浸没和生理温度（37°C））的组合导致胶原膜的拉伸强度下降约90%，而断裂应变增加到约145%。首次对胶原膜施加从准静态（0.0001 s）到中间态（0.001 s、0.01 s）再到动态（0.1 s、1 s）条件的不同应变率，并报告了应变率敏感性指数（m）。研究发现，随着应变率的增加，胶原蛋白表现出应变率敏感的硬化行为。指数m范围为0.02 - 0.2，在中间应变率（0.01 s）时有趋近于零的趋势，表明胶原蛋白在该状态下可能对应变率不敏感。通过对胶原膜超弹性参数的识别，发现奥格登模型为未来模拟提供了符合实际的结果。
