Ottawa Hospital Research Institute and University of Ottawa Eye Institute, Ottawa, Ontario, Canada.
Acta Biomater. 2013 Aug;9(8):7796-805. doi: 10.1016/j.actbio.2013.04.014. Epub 2013 Apr 22.
We have previously shown that recombinant human collagen can be crosslinked with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) to fabricate transparent hydrogels possessing the shape and dimensions of the human cornea. These corneal implants have been tested in a Phase I human clinical study. Although these hydrogels successfully promoted corneal tissue and nerve regeneration, the gelling kinetics were difficult to control during the manufacture of the implants. An alternative carbodiimide capable of producing hydrogels of similar characteristics as EDC in terms of strength and biocompatibility, but with a longer gelation time would be a desirable alternative. Here, we compared the crosslinking kinetics and properties of hydrogels crosslinked with a sterically bulky carbodiimide, N-Cyclohexyl-N'-(2-morpholinoethyl) carbodiimide metho-p-toluenesulfonate (CMC), with that of EDC. CMC crosslinking was possible at ambient temperature whereas the EDC reaction was too rapid to control and had to be carried out at low temperatures. The highest tensile strength obtained using optimized formulations were equivalent, although CMC crosslinked hydrogels were found to be stiffer. The collagenase resistance of CMC crosslinked hydrogels was superior to that of EDC crosslinked hydrogels while biocompatibility was similar. We are also able to substitute porcine collagen with recombinant human collagen and show that the in vivo performance of both resulting hydrogels as full-thickness corneal implants is comparable in a mouse model of an orthotopic corneal graft. In conclusion, CMC is a viable alternative to EDC as a crosslinker for collagen-based biomaterials for use as corneal implants, and potentially for use in other tissue engineering applications.
我们之前已经证明，重组人胶原蛋白可以与 N-(3-二甲基氨基丙基)-N'-乙基碳二亚胺（EDC）交联，以制造具有人眼角膜形状和尺寸的透明水凝胶。这些角膜植入物已经在 I 期人体临床研究中进行了测试。尽管这些水凝胶成功地促进了角膜组织和神经再生，但在制造植入物时，凝胶动力学很难控制。一种替代的碳二亚胺，能够产生与 EDC 具有相似特性的水凝胶，就强度和生物相容性而言，但凝胶时间更长，将是一种理想的替代物。在这里，我们比较了用空间位阻较大的碳二亚胺 N-环己基-N'-(2-吗啉代乙基）碳二亚胺甲磺酸酯（CMC）交联的水凝胶的交联动力学和性质与 EDC 的交联动力学和性质。CMC 交联可以在环境温度下进行，而 EDC 反应太快无法控制，必须在低温下进行。使用优化配方获得的最高拉伸强度相当，尽管 CMC 交联的水凝胶更硬。CMC 交联的水凝胶的胶原酶抗性优于 EDC 交联的水凝胶，而生物相容性相似。我们还能够用重组人胶原蛋白代替猪胶原蛋白，并表明这两种水凝胶作为全厚度角膜植入物在同种异体角膜移植的小鼠模型中的体内性能相当。总之，CMC 是 EDC 作为用于角膜植入物的基于胶原蛋白的生物材料的交联剂的可行替代品，并且可能在其他组织工程应用中也具有用途。
