| It is well known that titanium and its alloys?Ti6Al4V?are the most extensively used biomedical materials in orthopedic fields due to their favorable biocompatibility,high strength-to-weight ratio and excellent corrosion resistance.Moreover,the low elastic modulus of Ti-based implants is similar to the living bone.However,implant failures often appear because of the implant-associated bacterial infection.Meanwhile,the release of toxic elements such as Al and V as well as the poor osseointegration ability will cause the implant loosening and thus long-term adverse reactions may occur after surgery for the Ti6Al4 V implant,which more or less limits the application of Ti6Al4 V implants in medical field.Therefore,to address these problems,the surface coating with antimicrobial activity and nontoxic elements should be chosen as modification compositions to attain an acceptable antimicrobial property and cytocompatibility for the Ti6Al4 V implants.Currently,various techniques,such as anodization,micro-arc oxidization?MAO?and plasma immersion ion implantation,have been used to modify the surface of Ti-based implant materials.Among these approaches,MAO is a relatively convenient and effective technique for producing the microporous oxide coatings on the valve metals?Ti,Zr,Mg,etc.?surface.On the one hand,antibacterial elements?Ag,Zn,Cu,etc.?and bioactive elements?Ca,Sr and etc.?can be incorporated into the porous coatings by adding them in the electrolyte during the MAO process to enhance the antimicrobial ablity and bioactivity of implants.On the other hand,the microporous structure can provide a favorable biological adhesion to the surrounding tissue.Hence,in this study,we use magnetron sputtering to deposit Zr films on Ti6Al4 V surface and then conduct MAO to further introduce Zn into the ZrO2/TiO2 coating by a Zn-containing electrolyte.Ultimately,Zn-doped ZrO2/TiO2 porous coatings?Zn-ZrO2/TiO2?were in-situ fabricated on Ti6Al4 V implants for surface modification by a novel duplex-treatment technique and its cytocompatibility,antimicrobial property and corrosion resistance were further assessed.The main investigations are as follows:?1?The adhesive strength of Zn-ZrO2/Zr and Zn-ZrO2/TiO2 coatings on Ti6Al4 V substrate was evaluated by scratch test,and the result indicates that the Zn-ZrO2/TiO2 coatings of situ fabrication on Ti6Al4 V surface exhibit better adhesive behavior than others.?2?The microstructures,phase constituents and elemental states of Zn-ZrO2/TiO2 coating were characterized by scanning electron microscope?SEM?and X-ray photoelectron spectroscopy?XPS?.The results show that that the Zn-ZrO2/TiO2 coatings are porous,Zn and Zr of Zn-ZrO2/Ti O2 coatings exist in the chemical state of Zn O and ZrO2,respectively.?3?The Live/Dead staining and MTT assay were employed to evaluate the cytocompatibility of tested coatings.Plate-counting schemes were used to investigate the antimicrobial ablity of tested coatings.The biological experiments demonstrate that Zn-ZrO2/TiO2 coatings exhibit not only favorable cytocompatibility,but also excellent antibacterial activity against Gram-positive Staphylococcus aureus?S.aureus?.?4?Electrochemical tests indicate that the above-described duplex-treatment technique can endow with the excellent corrosion resistance for Ti6Al4 V implants.Meanwhile,Zn-ZrO2/TiO2 coatings also possess enhaced wear resistance. |
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