Star-shaped polymers of biodegradable aliphatic polyester, poly(ε-caprolactone), PCL, with different number of arms (three, four, and six) were synthesized by ring-opening polymerization initiated by multifunctional alcohols used as cores. As potential biomaterials, synthesized star-shaped poly(ε-caprolactone)s, sPCL, were thoroughly characterized in terms of their degradation under different pH conditions and in respect to their cytotoxicity. The in vitro degradation was performed in phosphate buffer (pH 7.4) and hydrochloric acid solution (pH 1.0) over 5 weeks. Degradation of sPCL films was followed by the weight loss measurements, GPC, FTIR, and AFM analysis. While the most of the samples were stable against the abiotic hydrolysis at pH 7.4 after 5 weeks of degradation, degradation was significantly accelerated in the acidic medium. Degradation rate of polymer films was affected by the polymer architecture and molecular weight. The molecular weight profiles during the degradation revealed random chain scission of the ester bonds indicating bulk degradation mechanism of hydrolysis at pH 7.4, while acidic hydrolysis proceeded through the bulk degradation associated with surface erosion, confirmed by AFM. The in vitro toxicity tests, cytotoxicity applying normal human fibroblasts (MRC5) and embryotoxicity assessment (using zebra fish model, Danio rerio), suggested those polymeric materials as suitable for biomedical application.

中文翻译：

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不同臂数星形聚（ε-己内酯）的水解降解及其细胞毒作用

可生物降解的脂肪族聚酯、聚（ε-己内酯）、PCL 的星形聚合物具有不同数量的臂（三、四和六），通过由用作核的多功能醇引发的开环聚合合成。作为潜在的生物材料，合成的星形聚（ε-己内酯）sPCL 在不同 pH 条件下的降解和细胞毒性方面得到了彻底的表征。在磷酸盐缓冲液 (pH 7.4) 和盐酸溶液 (pH 1.0) 中进行了 5 周的体外降解。sPCL 薄膜的降解后进行重量损失测量、GPC、FTIR 和 AFM 分析。虽然大多数样品在降解 5 周后在 pH 7.4 时对非生物水解稳定，但在酸性介质中降解显着加速。聚合物薄膜的降解速率受聚合物结构和分子量的影响。降解过程中的分子量分布显示酯键的随机断链表明在 pH 7.4 时水解的整体降解机制，而酸性水解通过与表面侵蚀相关的整体降解进行，AFM 证实了这一点。体外毒性试验、使用正常人成纤维细胞 (MRC5) 的细胞毒性和胚胎毒性评估（使用斑马鱼模型，Danio rerio）表明这些聚合物材料适合生物医学应用。而酸性水解是通过与表面侵蚀相关的整体降解进行的，AFM 证实了这一点。体外毒性试验、使用正常人成纤维细胞 (MRC5) 的细胞毒性和胚胎毒性评估（使用斑马鱼模型，Danio rerio）表明这些聚合物材料适合生物医学应用。而酸性水解是通过与表面侵蚀相关的整体降解进行的，AFM 证实了这一点。体外毒性试验、使用正常人成纤维细胞 (MRC5) 的细胞毒性和胚胎毒性评估（使用斑马鱼模型，Danio rerio）表明这些聚合物材料适合生物医学应用。