Ag-TiO2-PTFE纳米复合涂层的制备及抗菌机理研究

The formation of biofouling on the surface of medical implant materials generally causes biomaterial-related infection in clinical practice. Recently many studies had modified the surface of implants for reducing infection, but the coatings presented against bacterial activity impermanently. The researchers found that the incorporation of Ag-TiO2 coating on Ti matrix can improve the coating cohesion and have good biocompatibility. Based on our research, the super hydrophobic PTFE nanoparticles with non-stick property performed well for inhibiting bacterial adhesion instead of killing bacteria and improving bacterial removal. This project is going to prepare the Ag-TiO2-PTFE nano-composited coatings on Ti matrix by electroless plating technique in order to inhibit bacterial adhesion in the long term. The composition, morphology, mechanical properties, anti-bacterial adhesion, cytotoxicity and animal implantation performance of the nano-composited coatings will be investigated. According to extended DLVO theory, the modeling of the total interaction energy between surfaces and bacteria will be investigated and revealed the anti-bacterial adhesion mechanism. Based on modeling results, it will present a new idea and direction for the design of anti-infection implant materials in order to solve the implant infection thoroughly as well as pursue development in medical materials.

生物污染物附着在医用植入材料表面是诱发临床感染的重要原因之一。近年来很多学者对植入体材料进行表面改性研究，但都不能持久抗菌达到长期抗感染效果。研究发现Ag-TiO2修饰Ti基底不仅提高涂层的结合力，还具有较好的生物相容性。我们前期研究表明聚四氟乙烯纳米颗粒(PTFE NPs)由于具有超疏水性可从物理方法直接抑制细菌附着而非杀菌，还可以促进生物污染物从表面移除。据此本研究拟利用化学镀方法将PTFE NPs掺入Ag-TiO2内，制备双纳米颗粒协同修饰Ti的复合涂层，可更加高效持久抑菌从而起到防止植入体感染的作用。通过对涂层的结构表征及机械性能等进行测试，同时评估细菌吸附实验、细胞毒性试验与动物植入实验，验证新型涂层的持久抑菌效果。根据胶体稳定性理论，建立表面和细菌之间的相互作用模型，以揭示涂层抗菌的机理，为植入体材料改性技术提供新的设计思想和理论基础，推动生物医疗材料的发展。

近年来，由于钛植入体在医疗材料中存在严重的感染问题，很多研究试图对钛进行了表面修饰,但是都还不能解决感染问题。研究发现以Ti为基底的Ag-TiO2涂层具有优良的抗菌性可以短期内降低感染率，利用Ag的广谱杀菌能力和TiO2的光催化性能。为了提高长期持续有效的抗菌性能，本项目采用化学镀技术在Ti基底制备出Ag-TiO2-PTFE涂层，结合Ag-TiO2涂层的抗菌性能以及PTFE纳米颗粒的高效抗吸附性达到保持生物材料机械性能的同时从根本上抑制细菌的附着，可更加持久性降低植入体感染的问题。综合运用电子扫描电镜、原子力显微镜等对涂层进行表观形貌分析，粗糙度等到明显降低；利用x射线衍射仪、x射线光电子能谱等表征分析元素成分和含量；采用胶体稳定性理论分析表面和细菌之间的相互作用机理并建立模型，并利用新的涂层进行验证其长期抗菌性能和生物相容性。本研究为进一步改进涂层提供设计理念和方向，为实现长期抗菌及良好生物相容性的植入体材料提供理论基础。