Antibacterial Properties Of Silver Ion Implanted Titanium Dioxide Nanotubes

The outstanding physical and chemical properties and biocompatibility of titanium and its alloy of metal materials has led them to a wide application in biomedical field,which thus became the key material most commonly seen in the repair and replacement of hard tissue.However,recent studies have indicated that this material raises risks of post-surgery infection because of its poor anti-bacterial capability,suggesting the importance of physical improvement of TNTs.In this study,vertical TiO₂nanotubes were grown in pure titanium substrate by anodic oxidation method,followed by injections of different doses of Ag⁺,from which the products(Ag⁺-TNTs)were harvested after annealing treatment.The surface morphology,microstructure and composition of Ag⁺-TNTs were characterized by SEM,XRD,Raman,XPS and EDAX;The hydrophilicity and corrosion resistance of Ag⁺-TNTs were investigated by surface wettability test and corrosion resistance measurement.Finally,antibacterial experiments of Ag⁺-TNTs were conducted upon the conditions of natural lighting,UV lighting,darkness and treatment of gentamicin,respectively.The proliferation of E.coli was then evaluated using SEM and Fourier infrared tester to analyze the antibacterial performance of Ag⁺-TNTs and the underlying mechanisms in different conditions as mentioned above.The results are as follows:(1)Injection of Ag⁺changed the surface morphology of TiO₂nanotubes.The increase in the injection dose of Ag⁺has led to a significant decrease of floccule on the surface of TiO₂nanotubes and the degree of surface fragmentation with its coral-like structure maintained.Meanwhile,the crystallization effect of TiO₂nanotubes and the hydrophilicity and corrosion resistance were enhanced.(2)The antibacterial activity of Ag⁺-TNTs in the dark was enhanced with the increase of Ag⁺injection dose,because Ag⁺could lead to the aggregation of sulfhydryl complex and protein in E.coli.A rise-fall trend was observed in the photocatalytic activity of with the increase of Ag⁺injection dose,because the injection dose of Ag⁺would affect the number of electron-hole pairs formed by Ag⁺-TNTs under illumination.(3)The injection dose of Ag⁺did not affect the loading capacity of Ag⁺-TNTs with gentamicin.When Ag⁺-TNTs was loaded with gentamicin,the antibacterial effect of Ag⁺could be retained while gentamicin could be released to achieve antibacterial activity.(4)The surface morphology of Ag⁺-TNTs has antibacterial effect.With the increase of Ag⁺injection dose,A dynamic surface morphology of Ag⁺-TNTs was observed with the increase of injection dose of Ag⁺,which is beneficial for the impairment of growth and proliferation of E.coli..