| Biomedical cobalt-based alloys are widely used in the biomedical field due to their good wear resistance,corrosion resistance and excellent biocompatibility,especially for hard organism replacements such as joints and dentures.Previous studies have found that the addition of a small amount of antibacterial copper in the as-cast CoCrMo alloy could reduce the risk of bacterial infection during replacement surgery.However,due to the complex physiological environment coupled with artificial behavioral movements,the metal material implanted would cause metal ion released,material wear damaged and other problems,which can result in changing the implant material properties,or even implantation failure.Furthermore,implanted materials are easy to react with the body,causing cytotoxicity,and seriously threatening the long-term safe use of implanted materials and human health.In this paper,Cu element was selected as an antibacterial agent.The effect of copper addition and its content on the microstructure of antibacterial CoCrMo-Cu alloy was investigated by scanning electron microscopy.The corrosion and wear properties of the alloys were studied by electrochemical workstation and wear tester.The toxicity of copper ions and alloys to MC3T3-E1 was analyzed by morphological observation and CCK-8 method.The expression of osteogenic related genes(OCN,COL-I)was studied by Real-Time PCR.The main results are summarized as follows:Microstructure observation results showed that two kinds of second phase distributions of carbides and intermetallic compounds with obvious irregular shapes in CoCrMo,CoCrMo-2Cu and CoCrMo-4Cu alloys.In CoCrMo-2Cu alloys,copper mainly existed in the matrix in the form of solid solution while the CoCrMo-4Cu alloy had a distinct copper-rich phase at the junction of the second phase and the matrix.The results of corrosion resistance showed that the addition of copper element could slightly increase the self-corrosive current density of materials in simulated solution and reduce the corrosion resistance of the alloy,but the difference was not significant.The results of wear resistance test showed that the wear resistance of alloys with Cu added was lower than CoCrMo alloy.In addition,the wear rate of the alloy in the cell culture medium containing fetal bovine serum was significantly reduced.Compared with the wear rates of alloys with different potentiostatic,it could be found that the larger the potentiostatic was,the higher the total wear volume of the alloys would be,but the volume loss caused by wear still played a dominant role,and the loss caused by corrosion played a secondary role.By detecting the cytotoxicity and osteogenesis related gene expression level,it was found that when the copper ions concentration in the range of 1×10-4 mol/L?1×10-6 mol/L,the cells spreaded out in the culture plate in a rhombic and long spindle shape.They grew well.When the concentration of copper ion reached 1×10-3 Hol/L,all the cells died and floated in the cell culture medium in a spherical shape Besides,the concentration of copper ions at low concentration promoted the expression of osteogenic genes in cells,with 1×10-6 mol/L being the most obvious.Compared with the blank control group,the cells on the surface of the CoCrMo-Cu alloys grew well,and the relative growth rate of the cells reached more than 85%,and the expression of OCN and COL-I genes reached more than 80%,which indicated that the alloys had good cell compatibility. |
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