Investigation on the mechanical properties of contracted collagen gels as a scaffold for tissue engineering
Investigation on the mechanical properties of contracted collagen gels as a scaffold for tissue engineering
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DOI：
10.1046/j.1525-1594.2003.07187.x
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发表时间：
2003-01-01
影响因子：
2.4
通讯作者：
Umezu, M
中科院分区：
文献类型：
--
作者：
Feng, Z;Yamato, M;Umezu, M
本文通过单向拉伸实验，对收缩胶原凝胶的力学性能进行了研究。在100 mm直径的塑料皿中制备大的I型胶原-Dulbecco改良Eagle培养基（DMEM）凝胶（每个凝胶体积为26 ml，胶原浓度为1.67 mg/ml），每个凝胶填充有约2.5 x 10（6）个人成纤维细胞，用白蛋白预涂，使凝胶在DMEM中漂浮。将这些相同处理的凝胶分成三组，用于在不同培养期（2、4和10周）的机械测量。在前3天内发生快速收缩，然后在休息期间收缩缓慢，直到达到其原始大小的约13%。收缩胶原凝胶的应力-应变曲线在低应力区表现出指数行为，然后是线性区，屈服点，最后是达到最大应力的极限应力点。随着培养时间的延长，胶原纤维的机械强度先增加后降低，可见胶原纤维在培养过程中形成并被强制向拉伸方向定向。观察到应力松弛和循环蠕变现象。基于凝胶的透射电子显微镜（TEM）形貌分析，提出了能够再现凝胶流变现象的非线性粘弹塑性本构关系。本实验表明，人成纤维细胞显著收缩胶原凝胶，从而达到一定的机械强度，这使得它有可能成为组织工程的支架。然而，必须考虑进一步的方法来通过几倍来增强机械强度。同时，在结构的制作和应用中，应考虑流变现象。
In this article the mechanical properties of contracted collagen gels were investigated thoroughly by means of uniaxial tensile test. Large type I collagen-Dulbecco's Modified Eagle Medium (DMEM) gels (each was 26 ml in volume, 1.67 mg/ml collagen concentration), each populated with about 2.5 x 10(6) human fibroblasts, were made in 100 mm diameter plastic dishes precoated with albumin for floating the gels in DMEM. Such identically treated gels were divided into three groups for the mechanical measurements at different culture periods (2, 4, and 10 weeks). Rapid contraction occurred within the first 3 days and then the contraction went slowly in the rest period until it reached about 13% of its original size. The stress-strain curve of the contracted collagen gels demonstrated an exponential behavior at low stress region, followed by linear region, a point of yielding, and finally an ultimate stress point at which the maximum stress was reached. The mechanical strength increased in the first few weeks and then decreased as the culture went on. It is obvious that the collagen fibrils formed and were forced to orientate to the tensile direction after the test. The stress relaxation and cyclic creep phenomena were observed. Based on the morphological analysis of transmission electron microscopy (TEM) of the gels, a nonlinear visco-elastic-plastic constitutive formula was proposed, which was able to reproduce the rheological phenomena of the gels. This experiment shows that the human fibroblasts significantly contracted collagen gels so as to achieve certain mechanical strength, which makes it possible to be a scaffold for tissue engineering. However, a further method to reinforce the mechanical strength by several folds must be considered. Meanwhile, the rheological phenomena should be taken into account in the fabrication and application of the structure.