Poly(carbonate urethane) and poly(ether urethane) biodegradation:: In vivo studies
Poly(carbonate urethane) and poly(ether urethane) biodegradation:: In vivo studies
复制标题
DOI：
10.1002/jbm.a.30002
复制
发表时间：
2004-06-01
影响因子：
4.9
通讯作者：
Hiltner, A
中科院分区：
文献类型：
--
作者：
Christenson, EM;Dadsetan, M;Hiltner, A
在保持生物相容性和机械性能的同时，已经使用了几种策略来增加医用级聚氨酯的生物稳定性。一种方法是对敏感的软段进行化学修饰或替换。目前，由于聚碳酸酯软段的氧化稳定性提高，聚碳酸酯聚氨酯(PCU)正被评估为医疗器械中聚醚聚氨酯(PEUS)的替代品。初步的体内和体外研究表明，PCU的生物稳定性优于PEUS。虽然一些研究已经报道了这些新的聚氨酯在体外降解的证据，但还没有证据表明这些新的聚氨酯在体内显著降解，从而证实了降解机制。在这项研究中，考察了软段化学对商品级PU和PCU弹性体的相形态、力学性能和体内响应的影响。动态力学测试和红外光谱测试结果表明，PCU比PEU具有更好的相分离性能。此外，聚碳酸酯软段弹性降低导致PCU具有较高的弹性和较低的极限伸长率。在材料表征之后，采用皮下笼状植入方案研究了PEU和PCU的体内生物稳定性和生物相容性。支架植入研究和细胞培养实验结果表明，单核细胞在两种材料上黏附、分化、融合，形成异物巨细胞。现在普遍认为，这些黏附的巨噬细胞和异物巨细胞释放的活性氧物种启动了PU的生物降解。样品的衰减全反射-傅里叶变换红外分析提供了两种聚氨基甲酸酯中链断裂和交联的证据。这表明PCU也容易被贴壁细胞释放的试剂生物降解。这些结果加强了评价和了解多氯联苯的生物降解机制的必要性。(C)2004年威利期刊公司。
Several strategies have been used to increase the biostability of medical-grade polyurethanes while maintaining biocompatibility and mechanical properties. One approach is to chemically modify or replace the susceptible soft segment. Currently, poly(carbonate urethanes) (PCUs) are being evaluated as a replacement of poly(ether urethanes) (PEUs) in medical devices because of the increased oxidative stability of the polycarbonate soft segment. Preliminary ill vivo and in vitro studies have reported improved biostability of PCUs over PEUs. Although several studies have reported evidence of in vitro degradation of these new polyurethanes, there has been no evidence of significant in vivo degradation that validates a degradation mechanism. In this study, the effect of soft segment chemistry on the phase morphology, mechanical properties, and in vivo response of commercial-grade PEU and PCU elastomers was examined. Results from dynamic mechanical testing and infrared spectroscopy suggested that the phase separation was better in PCU as compared with PEU. In addition, the higher modulus and reduced ultimate elongation of PCU was attributed to the reduced flexibility of the polycarbonate soft segment. Following material characterization, the in vivo biostability andbiocompatibility of PEU and PCU were studied using a subcutaneous cage implant protocol. The results from the cage implant study and cell culture experiments indicated that monocytes adhere, differentiate, and fuse to form foreign body giant cells on both polyurethanes. It is now generally accepted that the reactive oxygen species released by these adherent macrophages and foreign body giant cells initiate PEU biodegradation. Attenuated total reflectance-Fourier transform infrared analysis of explanted samples provided evidence of chain scission and crosslinking in both polyurethanes. This indicated that the PCU was also susceptible to biodegradation by agents released from adherent cells. These results reinforce the need to evaluate and understand the biodegradation mechanisms of PCUs. (C) 2004 Wiley Periodicals, Inc.