具有骨诱导活性多级仿生人工骨的构建及其促进骨缺损修复的机理研究

Bone tissue engineering graft is one of the most promising ways to repair bone defects. The bionic property of composition, structure and function of tissue engineering scaffolds are the key factors that affect the repair efficiency of bone defects by tissue engineering grafts. Our research group developed bionic mineralized collagen, which had good biocompatibility, and the composition was close to the natural bone matrix. In this study, to simulate natural bone structure and mechanical properties, the mineralized collagen was prepared by freeze-drying and pressure processing technology to fabricate two kinds of scaffolds, the porous bone scaffold (cancellous bone) and dense bone scaffold (cortical bone). Bionic modeling and secondary molding techniques were used to prepare the multi-level bionic artificial bones with porous- dense composite structure. The mechanical properties, interfacial binding and osteogenic properties were evaluated. The influence of structural design and interface on the biological and mechanical properties of scaffolds was studied. The BMP-2 derived functional peptide was grafted onto the material by chemical modification method to prepare the multi-level biomimetic artificial bone complex system with osteoinductive activity, and its sustained release property and biological activity was evaluated. Establish bone defect model and study the effect of scaffold composition, structure, activity factor and physicochemical properties on bone defect repair and the related mechanism. And finally through this study, a highly bionic artificial bone graft was developed, which may provide a new kind of material and idea for the treatment of clinical bone defect and nonunion.

组织工程骨是修复骨缺损最有前景的方法之一。组织工程支架材料的成分、结构和功能仿生是影响组织工程移植物修复骨缺损的关键因素。课题组前期研制了仿生矿化胶原，具有较好生物相容性，成分与天然骨基质接近。本研究模拟天然骨结构和力学特性，利用冷冻干燥和压力加工技术将矿化胶原制备成微结构和力学特性上仿生的多孔型（松质骨）和致密型（皮质骨）组织工程支架；利用仿生建模和二次成型技术制备具有多孔-致密复合结构的一体化多级仿生人工骨，通过评价其力学性能、界面结合力及成骨性能，研究结构设计与界面对支架生物与力学性能的影响规律；采用化学修饰方法将BMP-2源性功能多肽接枝到材料上，制备具有骨诱导活性的多级仿生人工骨复合体系，评估其缓释性能和生物学活性；通过建立骨缺损模型，研究支架组成、结构、活性因子及其理化性能对骨缺损的修复作用及其相关机制。最终研制一种高度仿生人工骨，为临床骨缺损和骨不连的治疗提供新材料和思路。

骨缺损的修复和功能重建是尚未解决的临床难题。组织工程骨是修复骨缺损最有前景的方法之一。组织工程支架材料的成分、结构和功能仿生是影响组织工程移植物修复骨缺损的关键因素。本课题探索了一种功能性仿生人工骨的制备新方法与新技术，并系统探讨了其理化性能、生物学与骨缺损修复效能。首先基于前期制备仿生矿化胶原，采用通过冷冻干燥和压力加工技术成功构建多孔骨修复材料（仿生松质骨）和致密骨修复材料（仿生皮质骨）。通过调整材料制备过程中的参数，能够改变仿松质骨矿化胶原支架微观形貌和力学性能。多孔骨修复材料抗压强度接近松质骨。致密骨修复材料微观形貌较为紧密并具有较好韧性，其抗压强度接近皮质骨。两种支架均具有良好生物相容性，能够促进成骨相关细胞黏附与增殖。建立了两种骨缺损动物模型，分别评价了两种结构骨修复材料的体内降解性能及修复效能。多孔骨修复材料具有一定的骨诱导性，植入缺损区域12周均有不同程度新生骨再生。致密骨修复材料具有良好体内生物相容性与力学强度，能与自体骨实现骨性融合。基于此，项目组成功制备具有多孔-致密双层紧密结合的多级仿生人工骨，与单纯多孔修复材料和致密骨修复材料相比，复合型支架拥有更好的生物学性能，兼具有力学支撑与成骨活性。初步构建了功能性多级仿生人工骨，并研究了支架成分、结构、活性因子及理化性能对骨缺损修复的影响。基于仿生矿化胶原制备的多孔骨修复材料、致密骨修复材料与具有复合结构的骨修复材料形成了自主知识产权。本课题为骨修复材料的设计与制备提供一种新方法，为骨修复材料的临床筛选、评价和改进提供基础科学数据。本项目相关研究成果在国内外期刊发表论文21篇，其中SCI收录7篇。授权国家专利13项，其中发明专利2项。