The Antibacterial Properties Of Super-hydrophobic Nano-Ag/TiO₂Nanotubes Of Ti Implant

BackgroundBacterial adhesion on the material surface is the key factor of implant-relatedinfection. Therefore, the most important strategy against implant infection is toconstruct an antibacterial coating. Super-hydrophobic surface can inhibit bacterialadhesion but does not have anti-bacterial effect. Nano-silver is characterized bybroad antibacterial spectrum, good thermostability and biosafety. But thesilver-coating prepared by conventional method suffers from the weakness such asfast release and antibacterial activity in a very short period.ObjectiveFirstly, we intend to investigate the ability of TiO₂nanotubes as the carrier fornano-silver and its prolonged antibacterial activity. Secondly, we intend to investigatethe feasibility of surface modification of nanosilver-loaded TiO₂nanotubes forsuper-hydrophobicity and its antibacterial ability. Thirdly, we intend to investigatethe influence of super-hydrophobic modification on silver release.Methods1. TiO₂nanotubes were prepared by electrochemical anodic oxidation method, andthe material characteristics were analyzed through SEM, EDS and XRD. Thesuper-hydrophobic surface was prepared through surface modification with PETS.2．Silver-loaded TiO₂nanotubes were prepared by pulse electrodeposition method.The physicochemical properties and silver release were evaluated through SEM,TEM, XPS, and ICPMS etc. The antibacterial activity, biocompatibility, and bloodcompatibility of silver-loaded TiO₂nanotubes were evaluated.3. The super-hydrophobic surface was prepared through surface modification ofsilver-loaded TiO₂nanotubes with PETS. The silver release was evaluated throughICPMS. The antibacterial activity of super-hydrophobic Nano-Ag/TiO₂nanotubes coating was investigated by in vitro and in vivo experiment.Results1. TiO₂nanotubes were uniformly distributed, with diameter of80nm-100nm andlength of200nm-400nm. After modified with PETS, the contact angle was168.2°.2. Silver particles （10-30nm） were uniformly distributed into TiO₂nanotubes. Thesurface silver content for sample5-300,10-300and20-300were4.08At%,1.23At%and0.2At%respectively.3. The silver release time of silver-loaded TiO₂nanotubes was longer than14days.All the silver-loaded samples can form obvious bacterial inhibition zone.4. Sample5-300,10-300and20-300had good biocompatibility and bloodcompatibility, basically had no effect on osteoblast proliferation, differentiation.5. The silver-loaded super-hydrophobic surface can effectively inhibit bacterialadhesion and kill the bacteria adhered thereon. The super-hydrophobic modificationhad significant inhibition effect on burst release and made silver release more stable.6. In vivo experiments showed that silver-loaded TiO₂nanotubes andsuper-hydrophobic silver-loaded TiO₂nanotubes can prevent postoperative infection.Conclusion1．Silver particles of nanoscale were uniformly distributed into TiO₂nanotubes bypulse electrodeposition method.2．The silver release time of silver-loaded TiO₂nanotubes was longer than14days,and the silver-loaded TiO₂nanotubes had better antibacterial effect andbiocompatibility.3． The silver-loaded super-hydrophobic coating has not only the inhibition effect onbacterial adhesion, but also antibacterial activity.4． The super-hydrophobic modification had significant inhibition effect on burstrelease and made silver release more stable.5． The in vivo animal experiments showed that silver-loaded TiO₂nanotubes andsuper-hydrophobic silver-loaded TiO₂nanotubes can prevent postoperative infection.