Construction Of MoS₂-based Composite Coatings On Ti And Photo-responsive Antibacterial Properties

Thanks to its excellent mechanical properties,strong corrosion resistance and good biocompatibility,biomedical Ti alloys have been widely used in biomedical fields,especially as implant materials.However,due to the biological inertia of these materials,Ti-based alloys cannot combine with surrounding tissues quickly after implantation,which leads to a series of side effects,and causes the final failure of implant surgery.In addition,although strict sterilization treatment has been done before the operation,it still easily suffers from bacterial infection caused by other factors during the period of post-surgery.Ti-based material has no self-antibacterial property.Once bacterial infection occurs,the bacteria will rapidly proliferate and adhere to the surface of the implant,which will induce the failure of implantation,and even lead to death in serious cases.Traditional antimicrobial strategies include organic antimicrobials such as antibiotics and inorganic antimicrobials such as metal ions,but because of drug-resistance and the toxic effects,antibiotics-free strategies have been developed to resist bacterial infection.In this thesis,molybdenum disulfide(MoS₂)photo-responsive antibacterial composite coatings were constructed on Ti alloys,which endow this material with rapid photo-responsive bacteria-killing ability.The antibacterial behavior and related mechanism have been explored in this paper.The research content includes the following three parts:1.Building chitosan/silver/molybdenum disulfide(CS/Ag/MoS₂)composite coatingsThe MoS₂ coating was synthesized on the surface of titanium by hydrothermal method.Titanium alloy loaded with MoS₂ coating was immersed in silver nitrate solution under vacuum condition,and the silver ions were adsorbed on MoS₂.Then silver ions were reduced to silver nanoparticles by ultraviolet light.Finally,Ag/MoS₂-Ti was soaked in chitosan solution to coat the chitosan.2.Photothermal and photocatalytic antibacterial behaviors of CS/Ag/MoS₂ have been investigatedA series of results show that CS/Ag/MoS₂ composite coating on the surface of titanium has good photothermal and photocatalytic effect.Materials with photothermal and photocatalytic properties are usually used as antibacterial materials.In this paper,the antibacterial effect of CS/Ag/MoS₂ composite coating on the surface of titanium was investigated,and it has a rapid and efficient bactericidal effect under 660nm light.The bactericidal mechanism of CS/Ag/MoS₂ composite coating on titanium was also discussed.