第三代生物材料应当兼备可降解性和生物活性，因此，材料的降解规律和细胞响应是新一代生物材料研发所需要解决的关键科学问题；但这些基本问题、尤其是关于材料降解这个经典问题的研究进展缓慢，严重制约了生物材料的发展。本申请项目侧重研究医用高分子的降解规律以及在材料降解过程中细胞的动态响应。申请人综合分析材料的本体降解机理和表面溶蚀机理以及综合运用水解和酶解方式、提出了智能型复合降解的新思路，有望整合PLGA等现有本体降解型高分子良好的加工性能和力学性能以及部分表面溶蚀型高分子的降解具有细胞环境响应的特征，可使得材料降解更加可控、降解动力学与组织形成动力学相匹配。项目还打算研究材料表面的细胞行为和含细胞条件下材料的降解，拟运用所合成制备的具有表面图案的模型化水凝胶考察材料本体发生变化时细胞在材料表面的动态响应，并计划对生物材料进行体内观察、建立部分典型材料体内降解和体外降解的相关性。

The third-generation biomaterial is thought to be both biodegradable and bioactive. So how to regulate biodegradability of a biomaterial and its cell responses has got to be key fundamental questions for development of new biomaterials. The corresponding research especially for material degradability is, however, rather limited. Herein, the application project is aimed to investigate degradation of medical polymers and corresponding dynamic responses of cells. Based upon comprehensive understanding of bulk degradation and surface erosion and also hydrolysis and enzyme degradations, the applicant put forward a combinatory degradation mode with some aliphatic polyesters such as PLGA as the basic matrix and with some enzyme-sensitive materials constituting a water-proof surface layer. By this way, the biomaterial might exhibit good processibilty and mechanical properties, and meanwhile a tunable and modified degradation profile, which could match the tissue-formation kinetics much better. The project will also examine cell behaviors on those modified surfaces and the biodegradability of materials in presence of cells. The dynamic cell responses on biodegradable polymers will also be studied on model biodegradable hydrogels with well-defined surface patterns. Furthermore, this key project in application is going to examine the in vivo biodegradation, and is ambitious to set up the relationship between in vitro and in vivo biodegradation profiles for some typical biodegradable polymers.