The Research On Biofunctionalized Hydroxyapatite Composite Coatings Deposited By Vacuum Cold Spray

With the rapid development of biomedical and materials,the research and exploitation of new biomaterials has become a hot research topic in the field of biomedical.Titanium alloys have been widely used in orthopedic implant surgery for their excellent mechanical properties,corrosion resistance and biocompatibility.However,titanium alloys can be attributed to biological inert materials,always leading to insufficient integration with surrounding tissue,ultimately results in the failure of implants surgery,therefore,improving the surface properties of titanium alloys with a clinical significance.Hydroxyapatite(HA)coatings has been widely employed in the surface modification of medical titanium alloys for the excellent biocompatibility and biological activity.While,there are many problems exist in HA coatings.Functionalization of HA coatings not only can keep the excellent biological properties of HA,but also can achieve related properties according to specific applications,such as mechanical properties,biocompatibility and antibacterial performance.In this paper,composite powder and coatings based on HA were prepared,biological performance of coatings were evaluated,thus providing basic information for the clinical application of new type HA-based composite materials.Mainly research contents and conclusions of this paper are as follows:(1)The preparation of HA-based composite powderHA-ND/BMP2 composite powder prepared with HA powder,ND particles and growth factor BMP2,and HA-GS composite powder was prepared by HA powder and antibiotics GS.Results show that carboxyl groups has been successfully modified on the surface of ND by oxidation methods.BMP2 has been loaded on ND by interaction of electrostatic force etc.(2)The preparation of biofunctionalization HA-ND composite coatingsBiofuncational HA-NDcomposite coatings were obtained by VCS at room temperature,coatings and powder have the same phase composition and nanostructures.Thickness of coatings is about 40-50 ?m,and with a dense structure.The XPS result of composite coatings demonstrated the existence of BMP2.Vickers hardness,elastic modulus and the friction and wear resistance are improved of HA coatings when addition of 0.1 wt.% ND.Cell adhesion and MTT results show that HA-ND,HA-ND/BMP2 composite coatings with nontoxicity and favorable biocompatibility,and the addition of BMP2 has significantly promoted cells adhesion and spreading,indiciting VCS technology successfully retained the osteoinductive activity of BMP2.(3)The preparation of HA-based composite coatings with favorable biocompatibility and extended antibacterial effectHA-GS compsite coatings were achieved by VCS technology.XPS result demonstrated the existence of GS in composite powder and coatings.The GS release result shows that HA-GS composite coatings with a sustained and extended release of GS.The antbacterial rete of HA-GS coatings and the HA-GScomposite coatings after GS released for up to 31 days are 98.08% and 93.91%,respectively,therefore,HA-GS composite coatings not only with sustained and extended release of GS,but also with extended antibacterial effect.Cells results show that HA-GS composite coatings also with well biocompatibility.