Enhanced Osteogenic Differentiation Of Reduced Graphene Oxide With Different Degrees Of Reduction In Vitro

Background:A report in 2004 about graphene sheets has initiated enormous scientific activity.Because of its high specific surface area and excellent optoelectronic performance,it has been widely studied and applied in medicine,optoelectronic industry and other fields.Graphene has been used to deliver anticancer water-insoluble drugs in 2008,and has been widely studied in tissue engineering and surface engineering.Studies have proved that graphene material can promote the adhesion,proliferation and differentiation of osteoblasts.Titanium and titanium alloy are widely used in dental implants owing to their favorable mechanical properties and biocompatibility.The biological property of implant surface is very important.The surface of implant is the part which has contact with human body.Promoting the formation of new bone,achieving ideal osteointegration has always been the goal of implant surgery between the surface of titanium implant and the implant site.At present,studies have shown that the presence of graphene materials can enhance the bioactivity of implant surface,promote adhesion and osteogenesis of osteoblast.In this experiment,we used chemical connection method to build graphene coating on the surface of titanium.Through cell experiments,we observed and analyzed the effect of different reduction degree of graphene oxide on surface activity and biocompatibility.The purpose is to explore the effect of different reduction degree of graphene oxide as coating material on osteoblast proliferation and osteogenic differentiation,and analyze the feasibility of promoting new bone formation and osteointegration of implant interface.Method:1.Graphene oxide(Go)was loaded on the surface of commercial pure titanium(Ti)by chemical method.Reduced graphene oxide(r GO)with different reduction degree was obtained by heating for 2h,4h and 6h respectively,which were recorded as Ti-2r Go,Ti-4r Go and Ti-6r Go respectively.2.Scanning electron microscopy(SEM)and Raman spectroscopy were used to verify the successful loading of graphene material on the surface of pure titanium.The reduction degree of graphene material was analyzed by X-ray photoelectron spectra(XPS).3.MC3T3-E1 cells were co cultured with the materials in vitro.Compare the ability of different reduction degree of graphene oxide in promoting the proliferation and osteogenic differentiation.Results:1.Images of SEM and Raman spectroscopy showed that graphene was loaded successfully on the surface of titanium sheet in the form of single layer.The results of XPS show that the ratio of oxygen groups in graphene decreases with the increase of heating time,which proves that the reduction degree of graphene is higer.2.The results of co culture showed that graphene material had good biocompatibility,and Ti-2r Go had the best ability to promote the proliferation and osteogenic differentiation of MC3T3-E1 cells.Conclusion:In this study,Go was loaded on the surface of pure titanium by chemical method,and reduction degree of graphene oxide were obtained by thermal reduction method.The results showed that Go and r GO coating had good biocompatibility,and Ti-2r Go had the best ability to promote cell proliferation and osteogenic differentiation.