兼具促成骨及抗菌性能钛基植入体生物功能性界面研究

Regarding the clinical challenges of titanium and titanium alloys implants being lack of osseointegration with surrounding bone tissue and potential bacterial infection, this project proposes a concept of constructing TiO2 nanotubes arrays as nano-reservoirs on titanium-based materials, which would be covered by layer-by-layer (LBL) polymer multilayered structures. By using the nano-reservoirs to load single/multi components of bioactive factors stimulating bone formation and antibacterial agents, it would be helpful for retaining their bioactivities. Through the design of biofunctional macromolecules for multilayered structures, it would achieve bacterial infection responsive (pH, hyaluronidase, etc.) controllable drug release. The project will employ three models (cell, bacteria, cell-bacteria co-culture) to systematically investigate the effects of the nano-reservoirs interface on the adhesion, proliferation and differentiation of mesenchymal stem cells/osteoblasts and bacteria, and subsequently to reveal the underlying molecular mechanisms by using RT-PCR and Western Blot techniques. Finally, the project will confirm the biological responses of titanium-based implants in vivo in respect to the bacterial inhibition deriving from methicillin-resistant staphylococcus aureus (MRSA) infection and new bone formation. The project would not only investigate the fundamental science issues on the interactions between biofunctional interface of titanium-based materials and cells/bacteria, but also afford scientific evidence and new technologies for the exploiting anti-bacterial implants for bone repair with original intellectual property rights.

针对钛及钛合金植入体与周边骨组织缺乏整合性及潜在术后感染的临床挑战，本项目提出在钛基材上以原位TiO2纳米管阵列及层层组装(LBL) 高分子多层结构封盖构筑纳米储池的设计构思。利用纳米储池加载单/多组元促成骨生物活性因子及抗菌剂，保持其生物活性。通过多层结构生物功能性大分子设计，实现细菌感染响应性(pH、透明质酸酶等)的药物可控释放。利用细胞、细菌、细胞-细菌共培养三种模式系统研究纳米储池界面结构对骨髓间充质干细胞、成骨细胞及细菌粘附、增殖、分化的影响规律。进而，利用RT-PCR及Western Blot技术探究其潜在分子机制。最后，以动物实验验证钛基植入体对以耐甲氧西林金黄色葡萄球菌(MRSA)为代表引起的细菌感染的抑菌性能及促新骨形成能力等体内生物学响应。本研究不仅将探究钛基材生物功能性界面与细胞、细菌相互作用的基本科学问题，而且为研发自主知识产权抗菌骨修复植入体提供科学依据和新技术。

钛基植入体植入体内后，面临两大临床挑战：缺乏与周边骨组织整合性及细菌感染，直接决定了植入成败及长期使用寿命。钛基材料植入体内后，时序性蛋白吸附、细胞粘附/增殖/分化、组织形成的生物级联反应都发生其表/界面。鉴于此，我们利用钛基材表面纳米储池加载生物活性物质、层层组装高分子多层结构封盖等策略开展研究。相关研究涉及生物功能性大分子筛选、合成与表征；钛基TiO2纳米管阵列储池界面构建与表征；钛基纳米储池界面体外生物学评价；钛基纳米储池界面植入体体内生物响应验证等研究内容。除了圆满完成相关研究内容，本项目还拓展了钛基材表面光热/光动力抑菌及促骨修复相关研究。具体研究内容包括：（1）钛基材表面纳米管储池抗菌界面设计及与细胞/组织相互作用；（2）钛基材微纳结构抗菌表界面构筑及生物学效应；（3）钛纳米管拓扑结构及储池调控干细胞分化分子机制及促骨组织修复；（4）钛材表面MOF复合涂层抗菌及促骨修复研究；（5）钛基材表面光热/光动力抗菌及促骨修复研究。.总体上讲，项目进展顺利，完成情况良好，在生物材料领域高质量期刊诸如Biomaterials (5)、ACS Nano、Applied Materials Today、Chemical Engineering Journal、Acta Biomaterialia、Journal of Materials Chemistry B等发表SCI论文24篇；获权国家发明专利4项，申请国家发明专利2项；培养国家级人才1名，博士后1名，博士研究生8名，硕士研究生5名，共计15名。各项指标都超过或成倍于合同要求的指标。已取得的“兼具促成骨及抗菌性能钛基植入体生物功能性界面” 研究成果，为今后进一步研发生物功能性钛基植入体用于临床骨修复打下了坚实的基础。