Construction Of Inorganic Nano-antibacterial Materials In Medical Titanium Implants And Its Biocompatibility Research

Nowadays,researches on biomaterials have been becoming a focused area around the world.As a result,there is an increasing demand for biomaterials which can replace damaged or deteriorated tissues.Among them,titanium(Ti)based biomedical implants have been widely used in dental and orthodontic fields due to their outstanding biocompatibility,osteoconductivity and mechanical properties.However,Ti-based implants are disabled to combine with the host well after implantation because of the innate bioinert of Ti,which may lead to serious problems such as thrombosis and implant surgery failed.In addition,in spite of the fact that there are strict sterilization requirements in both the implant production and clinical operation procedures,post operative infections caused by bacteria from skins,blood,and surgical operators cannot be avoided.The resulting series of complications and possible postoperative surgeries may create not only extra cost of treatment,but also pains on patients.Traditionally,the primary choice in clinical treatment on infections is to take different kinds of antibiotics.But researchers have found that long-term use of these drugs may result in drug-resistant bacteria.In contrast,inorganic antibacterial agents can effectively inhibit bacterial growth and avoid the risk of producing resistant strains.Based on problems mentioned above,basic contents of this thesis are as follows:1.Modification of Ti surface by ALD deposited ZnO and alkali-heat treatment.Ti plates were first modified by alkali-heat treatment to form a porous structure on the surface,which provided a large specific surface area,plenty hydroxyl groups and betterbiocompatibility.Then,different thickness of ZnO nano films were deposited on the surface of alkali-heat treated Ti samples by ALD,endowing Ti plates with self-antibacterial activity.The results indicated that alkali-heat treated Ti samples were hydrophilic and biocompatible,while samples with ZnO films could inhibit the growth of bacteria.2.Atomic layer deposition of ZnO coatings with carbon nanotubes and chitosan/dopamine on Ti surface.In this part,multiwall carbon nanotubes were first treated with acid and then modified with chitosan or dopamine.Subsequently,the composites were coated on Ti surface by dip-coating several times.ZnO films were then deposited by ALD.The compositions,surface topography of the coated layer were comprehensively characterized.3.Biological modification of carbon nanotubes/chitosan on Ti surface by ALD deposited ZnO nanostructures.In order to improve biocompatibility of carbon nanotubes(CNTs),pristine CNTs were first treated by acid and then modified by chitosan(CS).Subsequently,CNTs/CS hybrids were deposited onto alkali-heat treated Ti samples by electrophoretic deposition(EDP).Finally,different thickness of ZnO nano films were deposited by ALD on CNTs/CS composition coated Ti surface.The results showed that the obtained nanostructures were evenly distributed on Ti surface.And the content of ZnO as well as morphologies could be adjusted by changing the parameters of ALD process.Antibacterial and biocompatibility experiments proved that these nanostructures on Ti surface provided considerable antibacterial efficiency and could regulate osteoblast behaviors.