Lai Victor K, Lake Spencer P, Frey Christina R, Tranquillo Robert T, Barocas Victor H
Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA.
J Biomech Eng. 2012 Jan;134(1):011004. doi: 10.1115/1.4005544.
Fibrin and collagen, biopolymers occurring naturally in the body, are biomaterials commonly-used as scaffolds for tissue engineering. How collagen and fibrin interact to confer macroscopic mechanical properties in collagen-fibrin composite systems remains poorly understood. In this study, we formulated collagen-fibrin co-gels at different collagen-to-fibrin ratios to observe changes in the overall mechanical behavior and microstructure. A modeling framework of a two-network system was developed by modifying our micro-scale model, considering two forms of interaction between the networks: (a) two interpenetrating but noninteracting networks ("parallel"), and (b) a single network consisting of randomly alternating collagen and fibrin fibrils ("series"). Mechanical testing of our gels show that collagen-fibrin co-gels exhibit intermediate properties (UTS, strain at failure, tangent modulus) compared to those of pure collagen and fibrin. The comparison with model predictions show that the parallel and series model cases provide upper and lower bounds, respectively, for the experimental data, suggesting that a combination of such interactions exists between the collagen and fibrin in co-gels. A transition from the series model to the parallel model occurs with increasing collagen content, with the series model best describing predominantly fibrin co-gels, and the parallel model best describing predominantly collagen co-gels.
纤维蛋白和胶原蛋白是体内天然存在的生物聚合物，是常用于组织工程支架的生物材料。胶原蛋白和纤维蛋白如何相互作用以赋予胶原蛋白 - 纤维蛋白复合系统宏观力学性能仍知之甚少。在本研究中，我们制备了不同胶原蛋白与纤维蛋白比例的胶原蛋白 - 纤维蛋白共凝胶，以观察整体力学行为和微观结构的变化。通过修改我们的微观尺度模型，考虑网络之间的两种相互作用形式，开发了一个双网络系统的建模框架：(a) 两个相互贯穿但不相互作用的网络（“平行”），以及 (b) 一个由随机交替的胶原蛋白和纤维蛋白原纤维组成的单一网络（“串联”）。我们凝胶的力学测试表明，与纯胶原蛋白和纤维蛋白相比，胶原蛋白 - 纤维蛋白共凝胶表现出中间性能（极限抗拉强度、破坏应变、切线模量）。与模型预测的比较表明，平行和串联模型情况分别为实验数据提供了上限和下限，这表明在共凝胶中的胶原蛋白和纤维蛋白之间存在这种相互作用的组合。随着胶原蛋白含量的增加，发生从串联模型到平行模型的转变，串联模型最能描述主要为纤维蛋白的共凝胶，而平行模型最能描述主要为胶原蛋白的共凝胶。
