Preparation of soft and hard biodegradable materials for tissue engineering

1.我们设计了一种具有生物可降解性和温度响应的水凝胶，用于组织工程中的三维基质。该材料来源于两种预聚物，即具有活化羧基的IPAAm共聚物和具有聚（Ala-co-Gly）接枝链的IPAAm共聚物。每一种水预聚物在瞬间形成的水凝胶和生成的水凝胶混合后，其体积相变温度在37℃左右。此外，我们证实了低于和高于转变温度的酶降解。在膨胀良好的条件下，水凝胶逐渐降解。该结果提示该水凝胶可用于三维细胞培养体系。为获得以异丙基丙烯酰胺为骨架的功能单体，设计合成了新型单体。这些是2-羟基异丙基丙烯酰胺，N，N-二甲基氨基异丙基丙烯酰胺。由IPAAm和这些单体组成的共聚物可以有效地调节过渡温度或改善细胞与合成基质的相互作用。为了获得易于设计理想形状的硬质可生物降解材料，我们制备了轻交联聚（ε-己内酯-共丙交酯）。实际上，熔点（软化点）等热性能与交联材料中己内酯和丙交酯的组成密切相关。以常规培养的HeLa细胞为模型细胞，检测细胞在制备的膜状材料上的粘附情况。有趣的是，细胞的粘附和生长依赖于己内酯和丙交酯的组成。生长速度与组织培养聚苯乙烯（TCPS）相当，有时甚至更好。我们还用模型蛋白、白蛋白和牛血清研究了交联材料对蛋白质的吸附。结果表明，材料表面附着较多的蛋白质，细胞黏附和生长较好。从这些项目中，我们成功地获得了酶降解水凝胶和交联聚（ε-己内酯-共丙交酯）两种可用于组织工程的聚合物材料。少

1.Soft MaterialsWe designed the hydrogel which has biodegradability and a temperature response for the three-dimensional matrix in tissue engineering. The materials was derived from two kinds of prepolymer, that is, IPAAm copolymer with activated carboxyl groups and one with poly(Ala-co-Gly) grafted chains, respectively. Only mixing of each aqueous prepolymer instanlt formed hydrogel and resulting one showed a clear volume phase transition temperature around 37℃. Moreover, we confirmed the enzymatic degradation below and above the transition temperature. In the well-swelled condition, the hydrogel was degraded gradually. This result suggested the hydrogel would be used for three-dimensional cell culture system.To obtain the functional monomer with isopropylacrylamide backbone, we designed and synthesized new type of monomers. These are 2-hydroxyisopropylacrylamide, N,N-dimthylaminoisopropylacrylamide. The copolymer comprising IPAAm and these monomers would be effective to modulate the … More transition temperature or to improve the cell ineraction with the synthesized matrix.2.Hard MaterialsTo obtain the hard biodegradable materials with easiness to design the desirable shape, we prepared the light-cross-linkable poly(ε-caprolactone-co-lactide). Actually, thermal propertied such as the melting points (softening points) closely depended on the composition of the caprolactone and the lactide in the cross-linked materials. We checked the cell adhesion on the prepared membrane-shaped materials using the model cell, conventionally cultured HeLa cell. Interestingly, the cell adhesion and growth depended on the composition of the caprolactone and the lactide. The rate of the growth is comparable to that of the tissue culture polystyrene (TCPS) or sometimes better. We also investigated the protein adsorption on the cross-linked materials using model protein, albumin and bovine serum. From the results, More protein adhered on the the materials that showed more cell adhesion and growth.From these projects, we succeeded the two types of the polymeric materials, such as enzymatically degradable hydrogels and cross-linked poly(ε-caprolactone-co-lactide) and these are useful for the tissue engineering. Less