Abstract: In order to overcome the drawbacks of poor mechanical strength and too fast degradation of chitosan films, poly(lactic acid-co- malic acid) (PML) was prepared by an "one-step" method, and the carboxyl content and hydrophobicity of the copolymers could be adjusted by changing the molar ratio in feed. The copolymers were added to chitosan for complexation in aqueous solutions, and the modified complex films were prepared via a casting/solvent evaporation technique. The composite films were characterized by FT-IR and TGA, and their mechanical properties, degradation and vitro cytotoxicity were investigated. The influence of molar ratio between MA and LA in feed on the structure and properties of the films were studied. The results showed that in the molar ratio of n_MA:n_LA= 1:1.5, the tensile strength of the film is 54.8MPa, breaking elongation is 10.7%, mass loss is 50% after 28 days and the 3T3 cell viability profiles are 98.7%. It is concluded that the composite film can be formed by polyelectrolyte interaction between chitosan and PML. The flexibility of the composite film is improved and degradation time is extended compared to pure chitosan film. The film properties can be adjusted by changing components in the copolymers. The composite films are non-cytotoxic, biocompatible, and have potential applications as tissue adhesion prevention materials.

Key words: chitosan, poly(lactic acid-co-malic acid), polyelectrolyte composite film, adhesion prevention

摘要： 为了克服壳聚糖薄膜力学强度差和在体液内降解太快的缺陷, 首先用"一步法"合成了—COOH含量及疏水性可控的苹果酸与乳酸共聚物(PML), 再将共聚物与壳聚糖(CS)复合, 通过溶液浇铸-挥发的方法制备改性复合薄膜。通过红外(FT-IR)、热重分析(TGA)、力学性能测试、降解实验及体外细胞毒性实验等方法对复合膜进行分析, 研究L-苹果酸(MA)与D,L-乳酸(LA)的投料比(n_MA:n_LA)对复合膜性能的影响。结果显示:当n_MA:n_LA为1:1.5时, 该共聚物与CS的复合膜拉伸强度达到54.8MPa, 断裂伸长率为10.7%, 质量损失50%所需时间为28天, 细胞相对增殖率为98.7%。研究表明:通过共聚物与壳聚糖之间的聚电解质相互作用, 有效形成了结构均匀、性能改善的薄膜, 复合膜的柔韧性提高, 降解时间适当延长, 性能可由共聚物的投料比来调节。复合膜无细胞毒性, 生物相容性好, 作为手术后防组织粘连材料具有光明的应用前景。

关键词: 壳聚糖, 聚(苹果酸-co-乳酸), 聚电解质复合膜, 防粘连