Effect Of Nickel-free Austenitic Stainless Steel On The L929 Cells' Apoptosis With Flow Cytometry

ObjectiveMetal alloys using in human physiological environment,was one of the dental restorative materials applying to human body,had some invariable effect on life organisms.Biological compatibility evaluation was one of the important contents of researching biomedical metal materials.Nickel-free austenitic stainless steel was a new kind of metal materials, developed by Institute of Metal Research,Chinese Academy of Sciences.The material's excellent mechanical property had been validated by mechanics experiments,but its biocompatibility still needed further research.My experiment estimated nickel-free austenitic stainless steel and the other 6 metal alloys' biocompatibility on the view of cytobiology, by means of cell culture and flow cytometry detection.Through the comparison,we further evaluated nickel-free austenitic stainless steel's biocompatibility.Methods1.Cells cultureL929 cells were cultivated and passaged with RPMI 1640 cell medium containing 10% fetal calf serum in the incubator of 37℃and 5% CO2.2.Detecting cell apoptosis in different stages of the cell apoptosis with flow cytometerCultured L929 cell with 5 metallic alloys'leaching liquor and their negative controls for 24 and 48 hours, and stained them with Annexin V-EGFP and PI,and then detected apoptosis of cell with flow cytometer.3.Observing the apoptotic cells with fluorescence microscopeA drop of the group of cells suspension after dyeing liquid and slides, and covered glass cover, the cell fluorescence microscope fluorescent signals Annexin V-EGFP green fluorescent signals red, PI.ResultsCells in the experimental group could be observed apoptosis cells with the fluorescence microscope after Annexin V-EGFP and PI staining.The detected consequence with flow cytometry indicated that the apoptosis rates of each interclass are different.The apoptosis rate of the gold alloy group was the minimum approaching to the negative control group.The apoptosis rate of the nickel-free austenitic stainless steel group was close to the gold alloy group.While other metallic alloys'apoptosis rates were far more than the gold alloy group,among which the one of nickel chromium alloy was the highest and much higher than the gold alloy group and the sequence was gold alloy,nickel-free austenitic stainless steel, cobalt chrominum alloy,317L austenitic stainless steel,nickel chromium alloy descent one by one.Conclusions1. The results of five metallic alloys'biocompatibility evaluation as follows:gold alloy,nickel-free austenitic stainless steel,cobalt chrominum alloy,317L austenitic stainless steel,nickel chromium alloy.2. Nickel-free austenitic stainless steel may be considered to be applied to clinic.