Study On The Biocompatibility Of Novel Antibacterial Coating On Titanium

Objective To explore the effect of different concentrations of polydimethylsiloxane/chlorhexidine gluconate（PDMS/CHG）coatings on the biocompatibility of titanium surfaces.And provide a theoretical basis for the future use of this antibacterial coating to prevent peri-implant diseases.Methods The titanium sheets polished to 7000 mesh with sandpaper were randomly divided into five groups,one group was not treated as the blank control group,marked as the Ti group,and the other four groups were the experimental groups,followed by the PDMS group（only treated with PDMS）and the C1 group,（PDMS and 0.2mg/ml CHG treatment）,C2 group（PDMS and 0.4mg/ml CHG treatment）,C3 group（PDMS and0.8mg/ml CHG treatment）.First,the surface morphology of each group of titanium sheets was analyzed with a scanning electron microscope to observe the uniformity and density of the coating.Elemental composition analysis was performed on random three regions of two titanium sheets.The titanium sheets were then transferred to 24-well plates,and rat gingival fibroblasts（RGFs）were inoculated to the surface of each group of titanium sheets for 12 hours.After 12 hours of co-culture,the RGFs cytoskeleton was stained with FITC-labeled phalloidin.Confocal Laser Scanning Microscopy（CLSM）was used to observe cell morphology;CCK-8 kit and microplate reader of multi-wavelength were used to measure the optical density at 450 nm per well at 1,4 and 7 days of cell culture.After inoculating RGFs on the surface of the titanium sheet for 24 hours,the RGFs was stained with AO/EB double staining kit,and the cell live and dead was observed under CLSM to judge the biocompatibility of the coating.Results Firstly,the surface morphology of titanium sheets in each group was found that the corresponding coating was formed on the surface of titanium sheets in each experimental group except the blank control group.Although the surface of titanium sheets in C1 and C2 groups also formed coating,it was not dense enough,but a uniform and dense coating was formed on the surface of titanium sheets at the concentration of0.8mg/ml（C3 group）.Then,the surface elements in three regions of two titanium sheets in C2 group were analyzed by X-ray energy spectrum.The results showed that chlorine was successfully grafted.The cytoskeleton on the surface of titanium sheets in each group was stained with FITC labeled phalloidin.The results showed that the cells on the surface of titanium sheets in each group were well extended under confocal microscope,the cytoskeleton was clear,polygonal,and pseudopodia extended around,which was basically the same as that in the control group.The cell proliferation was detected by CCK-8 kit,and the OD value of titanium surface cells cultured for 1,4 and 7 days in the above groups was detected.The results showed that although the OD value of each experimental group was different from that of the control group,the difference was not statistically significant（P > 0.05）.Finally,AO / EB double staining kit was used to detect the survival and death of cells on the surface of titanium tablets in each group.The results showed that a large amount of green fluorescence was observed on the surface of titanium tablets in each group,and red fluorescence was rarely seen。Conclusion The PDMS/CHG coating with a concentration not exceeding 0.8 mg/ml had no effect on the biocompatibility of the titanium sheet surface.In conclusion,the use of PDMS/CHG coating with concentration no more than 0.8mg/ml will not affect the biocompatibility of the titanium sheet surface,and this coating can be considered as a strategy to prevent peri-implantitis.