Viscoelastic Properties of Isolated Collagen Fibrils
Viscoelastic Properties of Isolated Collagen Fibrils
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DOI：
10.1016/j.bpj.2011.04.052
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发表时间：
2011-06-22
影响因子：
3.4
通讯作者：
Eppell, Steven J.
中科院分区：
文献类型：
--
作者：
Shen, Zhilei Liu;Kahn, Harold;Eppell, Steven J.
了解具有复杂分层结构的胶原组织的粘弹行为需要了解每个结构水平的特性。整个组织已被广泛研究，但很少有人知道在亚微米，纤维水平的机械行为。利用微机电系统平台，对从海参真皮中分离的胶原纤维进行了体外蠕变和应力松弛耦合试验。应力-应变-时间数据表明，孤立的原纤维表现出粘弹性行为，可以使用Maxwell-Weichert模型拟合。原纤维显示出123 +/-46MPa的弹性模量。使用双时间常数Maxwell-Weichert模型很好地拟合了时间依赖性行为，快速时间响应为7 +/- 2 s，慢速时间响应为102 +/- 5 s。纤维松弛时间小于组织水平松弛时间的文献值，表明组织松弛由非胶原组分（例如，蛋白聚糖）。每个样本测试三次，发现的唯一统计学显著差异是第一次测试的弹性模量大于随后的两次测试，表明胶原纤维的粘性对先前测试的历史不敏感。
Understanding the viscoelastic behavior of collagenous tissues with complex hierarchical structures requires knowledge of the properties at each structural level. Whole tissues have been studied extensively, but less is known about the mechanical behavior at the submicron, fibrillar level. Using a microelectromechanical systems platform, in vitro coupled creep and stress relaxation tests were performed on collagen fibrils isolated from the sea cucumber dermis. Stress-strain-time data indicate that isolated fibrils exhibit viscoelastic behavior that could be fitted using the Maxwell-Weichert model. The fibrils showed an elastic modulus of 123 +/- 46 MPa. The time-dependent behavior was well fit using the two-time-constant Maxwell-Weichert model with a fast time response of 7 +/- 2 s and a slow time response of 102 +/- 5 s. The fibrillar relaxation time was smaller than literature values for tissue-level relaxation time, suggesting that tissue relaxation is dominated by noncollagenous components (e.g., proteoglycans). Each specimen was tested three times, and the only statistically significant difference found was that the elastic modulus is larger in the first test than in the subsequent two tests, indicating that viscous properties of collagen fibrils are not sensitive to the history of previous tests.