Construction And Biological Properties Of ZnO Based Nanorod Arrays On Titanium Surface

With the aging of the population and the frequent occurrence of traffic accidents and other accidental injuries,the need for hard implants is gradually increasing.Medical titanium and its alloys have been widely used in the field of bone implants due to their excellent mechanical properties and good biocompatibility.However,medical titanium and its alloys do not have antimicrobial properties,leading to frequent bacterial infections after surgery.Clinically used injections or oral antibiotic therapy for treating bacterial infections associated with implant,but antibiotics cause harm to human body,and can lead to drug-resistant bacteria.Therefore,it is necessary to modify the surface of medical titanium and give it antibacterial properties.Zinc oxide(ZnO)is a kind of widely used broad spectrum antibacterial agent,and will not lead to drug-resistant bacteria,but it also has higher cytotoxicity,hinder its clinical application.To solve this problem,in this paper,ZnO nanorod arrays were firstly prepared on titanium surface by combining sol-gel method and hydrothermal method,and then titanium dioxide(Ti O₂)was deposited on the surface by atomic layer deposition technology to construct ZnO/Ti O₂composite films.In addition,silver sulfide and zinc sulfide nanorods(Zn S/Ag₂S)heterojunction films were fabricated by ion exchange method using zinc oxide nanorods array as template.The biocompatibility and antimicrobial properties of heterojunction films and their related mechanisms were studied.The main results are as follows:1.the ZnO nanorod arrays were successfully prepared on the surface of medical titanium by combining sol-gel method and hydrothermal method.Then,Ti O₂films of different thickness were deposited on the surface of ZnO nanorods by atomic layer deposition technology to study the effect of Ti O₂film thickness on the antibacterial properties of ZnO nanorods.The results show that the ZnO nanorods are hexagonal crystalline phase and grow along the C axis with good orientation.The Ti O₂film deposited by atomic layer is amorphous,and the ZnO/Ti O₂composite film still retains the structure of nanorod array.ZnO nanorods have good antibacterial properties,but poor biocompatibility due to the rapid release of large amount of Zn²⁺.After the deposition of the TiO₂ film,the antibacterial properties of the composite film decreased.The thicker the TiO₂ film,the slower the release rate of Zn²⁺,the weaker the antibacterial properties,but the better the biocompatibility.2.Zinc sulfide and silver sulfide(Zn S/Ag₂S)nanorods heterojunction structures were constructed using ZnO nanorod arrays as templates by continuous ion exchange method.Compared with ZnO nanorod arrays,Zn S/Ag₂S nanorod arrays have better biocompatibility.The light response of Zn S/Ag₂S nanorod arrays was increased.Under visible light irradiation,the release of reactive oxygen species could be promoted to realize rapid and efficient sterilization,and the antimicrobial performance was positively correlated with the content of Ag₂S.Under visible light,the antimicrobial efficiency of Escherichia coli and Staphylococcus aureus was nearly100%within 20 min.In addition,compared with ZnO nanorod arrays,Zn S/Ag₂S nanorod arrays have better biocompatibility.