Caruso Andrea B, Dunn Michael G
Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, MEB 424 P.O. Box 19, New Brunswick, New Jersey 08903, USA.
J Biomed Mater Res A. 2004 Apr 1;69(1):164-71. doi: 10.1002/jbm.a.20136.
The mechanical properties of anterior cruciate ligament (ACL) reconstruction scaffolds were evaluated after exposure to functional challenges in vitro: cyclic loading combined with various proteolytic enzymes. Scaffolds were prepared from collagen fibers that were uncrosslinked (UNXL), crosslinked with ultraviolet irradiation (UV), or 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC; 10 or 25 mM). Structural properties of scaffolds were determined following 1-h exposure to saline, trypsin, or bacterial collagenase, with and without simultaneous cyclic tensile loading (0 to 50 g; 0.5 Hz) in vitro. The breaking load and stiffness of UNXL and UV crosslinked scaffolds were significantly reduced by exposure to either trypsin or collagenase. Cyclic loads interacted synergistically with enzymes, rendering UNXL scaffolds untestable and further decreasing the breaking load of UV crosslinked scaffolds by approximately 35%. In contrast, the breaking load and stiffness of EDC crosslinked scaffolds, which were greater than those of UNXL or UV crosslinked scaffolds, were virtually unaffected by the same load and enzyme treatments. These results suggest that EDC is more effective than UV for crosslinking and stabilizing load-bearing collagen fiber ACL reconstruction scaffolds. Application of cyclic loads and enzymes may lead to development of physiologically relevant in vitro test methods for load-bearing scaffolds.
在前交叉韧带（ACL）重建支架暴露于体外功能挑战后，对其力学性能进行了评估：循环加载与各种蛋白水解酶相结合。支架由未交联（UNXL）的胶原纤维、经紫外线照射（UV）交联或用1-乙基-3-（3-二甲基氨基丙基）碳二亚胺（EDC；10或25 mM）交联的胶原纤维制备。在体外，将支架分别暴露于盐水、胰蛋白酶或细菌胶原酶1小时，同时施加或不施加循环拉伸载荷（0至50 g；0.5 Hz），测定支架的结构性能。暴露于胰蛋白酶或胶原酶后，UNXL和UV交联支架的断裂载荷和刚度显著降低。循环载荷与酶协同作用，使UNXL支架无法测试，并使UV交联支架的断裂载荷进一步降低约35%。相比之下，EDC交联支架的断裂载荷和刚度大于UNXL或UV交联支架，在相同的载荷和酶处理下几乎不受影响。这些结果表明，在交联和稳定承重胶原纤维ACL重建支架方面，EDC比UV更有效。循环载荷和酶的应用可能会导致开发出与生理相关的承重支架体外测试方法。
