Novel biodegradable segmented polyurethanes (SPUs) were synthesized with polycaprolactone diol, 4,4'-methylen bis (cyclohexyl isocyanate) (HMDI), and either L-glutathione or its constituent amino acids (L-glutamic acid, L-cysteine and glycine) as chain extenders. Fourier transform infrared spectroscopy analysis revealed the feasibility of obtaining polyurethanes through the presence of NH (Amide II), C-N, C-O, and C=O bands and the absence of NCO band. Differential scanning calorimetry and X-ray diffraction revealed that a semicrystalline polymer (T m = 42-52 °C; 2θ = 21.3° and 23°) was obtained in all cases, while dynamic mechanical analysis (DMA) revealed an amorphous phase (T g = -30 to -36 (o)C). These properties, in addition to their high molecular weight, led to high moduli and higher extensibilities when glycine and glutamic acid were used as chain extenders. Clotting times (Lee-White test) and activated partial thromboplastin time determined on these polyurethanes were longer than with glass. In addition, all synthesized SPU exhibited platelet activation indexes below the collagen type I positive control. Human umbilical vein endothelial cells viability was higher in SPUs containing either glycine or cysteine. The obtained results indicate that SPUs that use cysteine as chain extender are promising candidates for cardiovascular applications.

译文

:用聚己内酯二醇,4,4'-亚甲基双(环己基异氰酸酯)和L-谷胱甘肽或其组成氨基酸(L-谷氨酸,L-半胱氨酸和甘氨酸)合成新型可生物降解的分段聚氨酯(SPU) )作为扩链剂。傅里叶变换红外光谱分析揭示了通过存在NH(酰胺II),C-N,C-O和C = O谱带以及不存在NCO谱带获得聚氨酯的可行性。差示扫描量热法和X射线衍射表明,在所有情况下均获得半结晶聚合物(T m = 42-52°C;2θ= 21.3°和23°),而动态力学分析(DMA)显示出非晶相(T g = -30至-36(o)C)。当使用甘氨酸和谷氨酸作为扩链剂时,这些特性,除了分子量高之外,还导致了高模量和更高的延伸性。在这些聚氨酯上测定的凝结时间(李白试验)和活化的部分凝血活酶时间长于玻璃。另外,所有合成的SPU均显示出低于I型胶原阳性对照的血小板活化指数。在含有甘氨酸或半胱氨酸的SPU中,人脐静脉内皮细胞的活力较高。获得的结果表明,使用半胱氨酸作为扩链剂的SPU是有希望的心血管应用候选药物。

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