Prepration And Antibacterial Property Of Surface Coating On Medical Titanium

Metallic biomaterials have been widely used in hard tiussue repair because oftheir excellent mechanical properties and good biocompatibility. Usually, metallicbiomaterials are bioinert, their bioactivity could be improved thourgh surfacemodification. In this study, the surface of biomedical titanium was modified by twodifferent mthods to improve its anbacterial property.Firstly, TiO2nanotubes were prepared by anodization on the Tisubstrate.Amorphous TiO2nanotubes were transformed to anatase through heattreatment. Ag nanoparticles were deposited on TiO2nanotubes by polyol chemistryprocess, and the effect of AgNO3concentration on the morphology of Agnanoparticles deposited on TiO2nanotubes was invetigated. When the AgNO3concentration was7mM, Ag nanoparticles with uniform size were evenly distributedon the mouth and sidewall of TiO2nanotubes. The average size of Ag nanoparticleswas15nm.When the Ag-TiO2nanotubes sample was immersed in PBS，the relativelyhigh concentration of silver ion at initial phase indicateda rapid release of silver. Atthe latter stages (after three weeks), the reduction in the release rate of silver wasobvious and reached a stable vevel of0.2ppm finally.This release profile is suitable toreduce the risk of infection.The results of bacterial adhesion and antibacterial activityshowed that the Ag-TiO2nanotubes exhibited the strongest antimicrobial activity onboth E. coli and S. aureus, and it was attributed to the release Ag ion.The Ag-TiO2nanotubes irradiated with UV light exhibited much stronger antibacterialactivity than that placed in dark.The main reason was that thephotocatalytic reaction of TiO2could produce the reactive species with antibacterialactivity.On the other hand, the alkali treatment was used to introduce hydroxyl (-OH) tothe surface of Ti.The ε-poly-lysine (ε-PL) was grafted on the Ti substrate. The phasecomposition and structure of coatingand antibacterial activity were evaluated.Theeffect of ε-poly-lysine concentration on the morphology of ε-poly-lysine grafted Tiwas examined.The high-performance coating was prepared by chemistry modificationwith added5mg/ml ε-poly-lysine.The Ti-ε-PL samples considerably resistedthebacterial adhesion, which was due to the hydrophilic property of ε-poly-lysine.