Preparation And Properties Of Biological Functional Magnesium Coating On Surface Of Biomedical Materials For Orthopaedic Implants

Currently,metallic biomaterials and biomedical polymer materials used in clinical are biologically inert material which are not easy to integrate with the bone tissue, thus resulting in implantation failure with its loosening. Meanwhile, those biomaterials don't possess antibacterial properties, as a result, they can lead to implantation failure easily with the wound infection during implantation.Magnesium alloys are considered to be a new generation of revolutionary metallic biomaterials due to its closing to the desity and mechanical properties of natural hone, good biocompatibility, degradability in the body as well as the biological functional ability to promote new bone tissue forming. In addition,the degradation of magnesium may rapidly release hydroxide ions, which leads to the increase of local pH.The high alkalinity can inhibit the growth of bacteria leading to excellent antibacterial function. In this paper, the orthopaedic implant materials used in clinic widely are coated with magnesium to improve the bioactivities of the inert titanium alloy andpolymer material significantly.In this paper, pure magnesium coatings were successfully prepared on titanium and polyetheretherketone (PEEK) substrates by pulsed-bias arc ion plating and vacuum deposition,respectively.The paper optimized the process parameters by investigating different experimental parameters. The effects of different working pressures on the surface quality of pure magnesium coating gained by PBAIP were investigated.The effects of different working temperatures on the properties of pure magnesium coatings gained by VP were studied. The elements composition,degradable procperties in vitro of the coated material were analysised thoroughly.The properties of pure Mg coating on the surface of two kinds of substrates were studied by immersion test, antibacterial test and cell experiment. The main conclusions were drawn as follows:The temperature obviously affected the quality of pure magnesium coating prepared by vacuum evaporation. The particles size increase guadually with the evaporation temperature increase,and the coating thickness increase.s Compared with pure magnesium coating, the particle size of pure magnesium coating prepared by pulsed bias arc ion plating is one order of magnitude smaller than that of pure magnesium coating,and the surface particles are more homogeneous and compact with no obvious defects.The results of immersion tests in vitro showed that PEEK coated with magnesium exhibited better corrosion resistance than that of the Mg coating ontitanium alloy in vitro simulated body fluid because of no galvanic corrosion.The results of antimicrobial experiments showed that both magnesium alloy coating on titanium alloy and PEEK coated with magnesium had strong killing effect on Staphylococcus aureus and showed good antibacterial function.The results of cytotoxicity test showed that PEEK coated with magnesium andmagnesium coating on titanium alloy promoted rabbit bone marrow mesenchymal stem cells (rBMSCs) growth and proliferation.