仿生ECM蛋白水凝胶的合成及其骨修复性质研究

The ideal bone-repairing materials should possess the similar functions to those of the natural osteogenic extracellular matrix (ECM). Besides providing support for mesenchymal stem cells (MSCs), it is expected to mimic the functions of proteins in ECM for enhancing the adherence of MSCs, and promoting the differentiation of MSCs towards osteogenic cells. However, the current artificial ECM materials showed limited ECM functions, which cannot meet the clinical applications..This project aims at constructing the poly(amido amine)(PAMAMA)-based biomimetic hydrogel systems and explore their functions as ECM for bone repairing. The study will be focused on (1) preparation and characterization of hydrogels from modified PAMAM dendrimers with RGD or DOPA, and liner copolymers containing PEG, PLA units, adding rhBMP-2 in the hydrogels to construct the biomimetic ECM systems; (2) introducing mMSCs into the systems, performing 3D cell culture and biology test in vitro, from which XTT, cell morphology, migration characteristics of GFP-mMSCs in the hydrogels, ALP staining and activity and osteogenic gene expression will be detected; (3) establishing C57BL/6 mouse calvarial bone critical defect model and verifying the osteoinductive activity and degradation conditions of the systems in vivo.

理想的骨修复材料应具有与天然成骨细胞外基质(ECM)相似的功能，除对干细胞提供结构上的支持外，还可模仿ECM中蛋白质的功能，诱导干细胞的粘附并刺激细胞向成骨细胞分化。目前采用的材料均存在骨诱导能力不佳等诸多问题。项目拟选择不同的蛋白或多肽对PAMAM分子进行修饰，筛选具有生物相容性的线性聚合物，设计并合成基于PAMAM树枝状分子的水凝胶；进一步将生物活性成分RGD、多巴胺(DOPA)、人重组骨形态发生蛋白-2等引入水凝胶体系，构建既可增强材料粘附性又可激活细胞整合素受体，从而促进干细胞成骨向分化的“多功能”仿生ECM体系。项目将从细胞生物学和动物模型的角度对材料体系进行深入评价，为制备仿生骨修复材料提供新方法和理论依据。

项目NSFC81500894是从高分子化学及组织工程学的角度出发，研究体外模拟细胞外基质，进一步探索骨组织的再生等问题。项目对PAMAM分子进行修饰，筛选具有生物相容性的线性聚合物，设计并合成基于PAMAM树枝状分子的水凝胶；进一步将生物活性成分RGD、多巴胺(DOPA)等引入水凝胶体系，构建既可增强材料粘附性又可激活细胞整合素受体，从而促进干细胞成骨向分化的“多功能”仿生ECM体系。项目除完成了对两种水凝胶仿生体系构建的问题外，适当的涉及了纳米管对细胞外基质的影响等问题，在原有申请任务书基础上，研究内容更加丰富和完善，扩展了细胞外基质问题研究的范围，发表了较高水平的论文。项目已经围绕计划研究内容开展了多项实验，已经发表相关SCI论文4篇，均标注项目基金号，进一步的深入研究将在后续工作中继续展开。研究已获得的结论对我们深入理解细胞外基质的生物作用机制，对骨组织工程研究提供有益的帮助。