抗菌性矿化胶原仿生骨的制备及其修复种植体周围感染性骨缺损的研究

Biomimetically fabricated mineralized collagen based composite is one of the most promising materials for the future hard tissue replacement implants. Based on the results of our previous study which showed that the antimicrobial peptides of Pac-525 and KSL inhibited the mainpathogenic bacteria of peri-implantitis, maintain the balance of micro-ecology around the dental implants with no effect to the probiotics, we put forward a new idea aimed at bone tissue engineering biomaterials to peri-implantitis. A new biomaterial for bone tissue engineering scaffold with good antibacterial activity and high similarity with the natural bone structure is synthesized via collagen fiber self-assembly and biomimetic synthesis methods. Composite microsphere is used for controlled release system with antimicrobial peptides carrying, and then composites with the nano-hydroxyapatite/collagen based composite, which shows some features of natural bone in both composition and hierarchical microstructure. In this project, we focus on the modification of antimicrobial peptide on the nano-hydroxyapatite/collagen based composite and evaluate the properties of antibacterial bone substitute comprehensively. Using cell culture techniques, three dimensional distribution and growth of cells and nano-hydroxyapatite/collagen based composite modified with antimicrobial peptide bone-like constructs will be developed in vitro, including bone marrow stromal cells and bacterial cells. Simultaneously, antibacterial activity and bone regeneration ability will be evaluated through animal models of peri-implantitis. The development of antibacterial biomaterials as bone substitute and the success in tissue engineering of bone will be beneficial to dental implant.

从仿生矿化胶原基纳米晶羟基磷灰石骨组织工程材料出发，立足于前期实验筛选的抗菌短肽Pac-525和KSL具有抑制种植体周围炎主要致病菌、但不影响益生菌、利于维护种植体周围微生态平衡的特性，利用双重载药的缓释微球系统协载抗菌肽，并将其复合于与人松质骨的微结构和组成极为相似的纳米晶羟基磷灰石胶原人工骨修复材料，制备具有抗菌活性的、仿天然骨结构的骨组织工程支架材料。系统研究抗菌肽对矿化胶原人工骨的修饰过程，分析仿生人工骨材料的降解及缓释效果并从组织工程学的角度开展支架材料表面三维培养的细胞学实验和种植体周围炎的骨再生动物实验，综合评价抗菌肽修饰的矿化胶原仿生人工骨的抗菌性能和骨再生修复疗效，为临床治疗种植体周围感染、促进种植体周围骨缺损的再生修复提供高效的备选骨组织工程生态材料。

本研究采用电纺PLGA微球结合电喷壳聚糖微球的方法，运用BSA和CHA作为模型药物，制备电纺复合微球并对其完成理化和生物特性的系列表征，实现静电纺丝制备载药复合微球工艺参数的筛选；进一步完成协载rhBMP2和PAC525的复合微球制备并通过细菌学实验和细胞学实验评价和验证复合微球良好的物理形貌、粒径、载药率、药物缓释曲线、生物相容性及抑菌活性。以纳米晶磷酸钙胶原为基质，将PLGA载抗菌肽微球与矿化胶原均匀混合，利用冷冻干燥法，制备出具有抗菌/成骨双重活性的多孔支架材料。即，在PLGA微球结合乳化壳聚糖微球制备复合微球的基础上，制备协载复式微球的双功能矿化胶原支架，支架形成多孔结构，孔径主要集中在50-200µm，孔隙率达到70%，是与人体松质骨的成分和纳米尺度结构相同的人工骨材料，通过材料表面细胞和细菌的三维培养及Beagle犬牙种植体周围骨感染缺损的原位植入实验，证实抗菌性矿化胶原仿生骨材料具有良好的抗菌性能及骨再生疗效，探索并实现同时具有良好抗菌活性、优异的骨传导性、和适宜的生物降解性的新型骨组织工程材料的制备和评价，为最终开发出国际先进的国产骨组织工程材料提供了实验和数据基础。