Preparation And Performance Study Of Graphene Oxide Film On Medical Titanium Surface

Titanium and its alloys are widely used as surgical clinical implants due to its favourable ductility,fatigue resistance,low modulus of elasticity,easy processing and biocompatibility.However,titanium and its alloys are bioinert materials with poor osteogenic activity and no antibacterial property.To improve bioactivity of the titanium,Surface modification of titanium surface are needed to gain osteogenic activity and antibacterial ability.Graphene oxide is a two-dimensional sheet material with good biocompatibility,which could promote the osteogenic differentiation of bone marrow mesenchymal stem cells and has good antibacterial properties.Graphene oxide films can endow titanium surface both osteogenic and antibacterial properties.Graphene oxide has lots of oxygen-containing functional groups such as carboxyl group.Graphene oxide would be positively charged in the electrolyte by adsorbing the metal cation.Therefore,it is possible to prepare graphene oxide films on titanium surface by cathodic electrophoretic deposition technique.In this study,graphene oxide films were constructed on the titanium surface by cathodic electrophoretic deposition,and treated with hydrothermal treatment under different conditions.The main results are as follows:(1)Graphene oxide flms with metal ions were fabricated on titanium surface by electrophoretic deposition technique and then treated with hydrothermal treatment with urea and sodium hydroxide,respectively.Results show that graphene oxide film has nano-scale fold structure after cathodic electrophoretic deposition.The wrinkle structure is more obvious after urea treatment.Layered double hydroxide composite with graphene oxide intercalation was formed after hydrothermal treatment with sodium hydroxide.Results of cell culture showed that the urea-treated graphene oxide film was more favorable for both proliferation and differentiation of rBMSCs.The sodium hydroxide-treated graphene oxide film would inhibite the proliferation of rBMSCs but promote its osteogenic differentiation.(2)The antibacterial properties and osteogenic acitvity of graphene oxide films with hydrothermal treatment of different concentrations of urea were investigated.The results showed that the graphene oxidefilms significantly inhibited the adhesion and proliferation of escherichia coli and staphylococcus aureus,and the inhibition rates for both bacteria were almost 100%.The effects of different concentrations of urea hydrothermal treatment on the antibacterial properties and cell compatibility of graphene oxide films were investigated.The results showed that the graphene oxide film could significantly inhibit the adhesion and growth of escherichia coli and staphylococcus aureus by generating reactive oxygen species(ROS),and the bactericidal ratios reached 100%.The urea hydrothermal treatment could obtain nitrogen-doped graphene oxide films.As the urea concentration increased,the structure of graphene oxide was destroyed more seriously,which weaken the ability of graphene oxide to generate ROS,and eventually graphene oxide lost antibacterial properties.