Antibacterial Coating On Titanium Alloy Surface Based On Zinc Oxide Nanomaterials

With the development of medical technology and genetic technology in modern society,many diseases that once plagued human beings have been effectively controlled.However,a series of problems such as hard tissue damage caused by aging population and accidental injury still need to be studied and controlled.Hard tissue damage cannot be repaired by the human body itself;surgical implantation of medical implant materials is needed to promote bone recovery.Among many medical implant materials,titanium alloy is widely used in hard tissue repair due to its excellent mechanical properties and good biocompatibility.Especially in load-bearing orthopedic surgery.In addition,in clinical application,there are two urgent problems in titanium alloy medical implants:bacterial infection and rejection.Titanium alloy itself has no antibacterial properties.In the process of surgery,bacteria may attach to the surface of the implant or infect the wound due to improper operation and other problems,leading to wound inflammation that is difficult to heal.In severe cases,it is even necessary to carry out a second surgery for re-implantation,which increases the treatment cycle and cost of patients.On the other hand,due to the poor biocompatibility of the metal implant itself,it may cause rejection by the body,resulting in slow wound recovery.Clinically,antibiotics are mainly used to control inflammation by oral administration or injection.However,with the increasing use of antibiotics in recent years,a series of drug-resistant bacteria have emerged.Based on the above problems,this paper will build an antibacterial coating based on zinc oxide(Zn O)nanomaterials on the surface of titanium alloy to provide excellent antibacterial effect for medical titanium alloy and improve its biocompatibility at the same time.In this paper,different antibacterial mechanisms of zinc oxide in different surface coating systems were explored,and the antibacterial system was developed from uncontrollable to controllable by using Zn O.The main contents of this study are divided into the following three parts:1.Construction of poly(lactic-co-glycolic acid)(PLGA)/Zn O nanorods/silver(Ag)nanoparticles coating on the surface of titanium alloy.Zn O nanorods were grown on the surface of titanium substrate by hydrothermal method,andthen coated with PLGA polymer doped with Ag nanoparticles.Because the coating can release zinc ions(Zn2+)and silver ions(Ag+)at the same time,it has a good antibacterial performance and has a bactericidal effect of more than 96%on Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli.)In addition,the release of PLGA package Zn²⁺and Ag⁺can last for more than 100 days,ensuring the long-term sterilization effect.When tested with mouse cranial cells,the coating with 1 wt%and 3 wt%silver nanoparticles showed less cytotoxicity.The results showed that the PLGA/Zn O/Ag composite could provide a durable antibacterial effect and good cell compatibility.2.Doping structure of titanium dioxide nanotubes(TNTs)encapsulated with folic acid(FA)/Zn O quantum dot(QDs)on the surface of titanium alloy.TNTs were formed on the surface of titanium sheet by anodic oxidation,and vancomycin(Van)was loaded in the TNTs.Then,Zn O QDs/FA encapsulated nanotubes.This layer remains stable under normal physiological conditions,but slowly decomposes and releases antibacterial drugs in the slightly acidic environment after bacterial infection.The inhibition rate of this system to S.aureus increased from 60.8%to 98.8%with the p H decreased from 7.4 to 5.5.In addition,the system has good biocompatibility.3.Preparation of injectable hydrogels modified by carbon quantum dots(CQDs)/Zn O and study on photodynamic photothermal synergism for rapid and efficient antibacterial.An injectable hydrogel is formed by the carboxyl chelation of Zn²⁺at the ends of dopamine(DA)and FA cross-linked structural molecules.In addition,CQDs/Zn O nanoparticles were introduced into the hydrogel through polydopamine(PDA)coating,activated oxygen(ROS)and heat were rapidly generated when the hydrogel was excited by 660 nm and 808 nm light,giving the hydrogel a controllable and rapid bactericidal effect.The 3d network structure of hydrogels and extracellular matrix also makes the system have good biocompatibility.