The Study Of Biological And Physicochemical Effects Of Co-Cr Alloy In Different Processing Technology

Objective:This experiment used 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting, to research the cytotoxicity of different processing technology acting on fibroblast of mice(L-929) and detecting related indicators of biocompatibility such as apoptosis, to guide clinical application. Methods: 1. X-ray fluorescence spectrum composition analysis The round metal Co-Cr alloys with diameter of 25 mm and thickness of 1mm made by 3D printing, imported casting and domestic casting were bought from manufacturer. Metal specimen grind and polish with sandpaper step by step to the mirror. Measure X-ray fluorescence spectrum. 2. Rockwell hardness measurementMeasurement of metal specimens surface Rockwell hardness HRA, load 60 kg,average about 3 points. 3. The performance evaluation of the corrosion This experiment adopts three electrode system, potentiodynamic polarization curve is tested by the PAR 2273 electrochemical workstation, and data fit the measured results by Origin software. 4. Cytotoxicity study Use ethylene oxide to sterilize the polished metal and preparation of leaching solution with 1640 medium. With CCK8 method determination of 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting of leaching solution in cytotoxicity of mice fibroblasts(L-929), measuring the absorbance value of each hole in the 450 nm wavelength by enzyme standard instrument and do the statistical description, calculate the relative proliferation rate of cells. the results of the experiment disposed by SPSS17.0 statistical software, statistical analysis by nonparametric statistical Kruskal-Wallis test, P<0.05,which is Statistically significant. 5. The impact on the cell apoptosis The experiment chooses AnnexinⅤ-FITC/PI double marking method of determination of the effect on leaching solution by 3D printing Co-Cr alloy, imported Co-Cr alloy casting, domestic Co-Cr alloy casting acting on the cell apoptosis of mice fibroblasts(L–929), testing the situation of each group by flow cytometry, calculating the rate of apoptosis, the results of the experiment disposed by SPSS17.0 statistical software, statistical analysis by nonparametric statistical Kruskal- Wallis test, P<0.05,which is Statistically significant. Results: 1. X-ray fluorescence spectrum composition analysis Through the fluorescence spectrum composition analysis, found that each group metal composition and content of the specimens without too much difference. 2. Rockwell hardness measurement Through the Rockwell hardness tester measured 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting’s hardness were 70.6 HRA, 68.4 HRA, 65.2 HRA. 3.The performance evaluation of the corrosion By the part of corrosion current density, the corrosion resistance of different processing technic Co-Cr alloy can be described as following: 3D printing>imported Co-Cr alloy casting>domestic Co-Cr alloy casting. 4.Cytotoxicity study Both 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting have certain influence on cytotoxicity of mice fibroblasts(L–929).After 24 h, three groups reveal grade 1 in cytotoxicity, means no cytotoxicity. when it comes to 48 h till 72 h,they show grade 2, means slight cytotoxicity. And the different results from 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting acting on cytotoxicity of mice fibroblasts(L-929) is statistically significant, P<0.05. 5.Apoptosis effect 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting are given priority to the living cells and apoptotic rate between groups was statistically difference(P < 0.05). Conclude:Through the fluorescence spectrum composition analysis, we found that each group metal composition and content of the specimens without too much difference. Through the Rockwell hardness tester,we found that the hardness of 3d printing Co-Cr alloy is the hardest. Above all we can see domestic Co-Cr alloy casting has the best corrosion resistance, imported Co-Cr alloy casting is better and the 3D printing Co-Cr alloy is the best of the three. Analysis by cytotoxic test and cell apoptosis test, the research reported the biocompatibility of 3D printing Co-Cr alloy, imported Co-Cr alloy casting and domestic Co-Cr alloy casting acting on cytotoxicity of mice fibroblasts(L-929) is decreasing in proper order.