Effect Of Graphene Derivatives And Mg/Zn Ions On The Behaviors Of Human Gingival Fibroblasts

Titanium?Ti?is commonly used as prosthodontic materials,which has good biocompatibility and mechanical properties.However,its biologically inertness leads to poor combination with soft tissue,resulting in the invasion of bacteria,causing periimplantitis,which destroys the stability of the implants and even implants loosening or falling.Improving the soft tissue sealing ability is critical to guarantee the service life of Ti implants.As an important component of oral soft tissue cells,the response of human gingival fibroblasts?HGFs?to material surface is closely related to its soft tissue sealing performance.In this paper,graphene derivatives,magnesium and zinc were loaded on the surface of Ti samples to study their effects on the behaviors of HGFs and related mechanism.The main results obtained are as follows:?1?Graphene oxide?GO?was electrophoretic deposited on Ti substrate and then reduced by sodium borohydride and hydrazine hydrate to study the effect of sp²domains on the behaviors of HGFs.The experimental results showed that there were no changes of the surface morphology of samples loaded with GO after reduction,and the content of sp² domains as well as the defect density increased,which may make the size of sp² domains decrease in reduced GO.HGFs on the surface of samples modified with GO or reduced GO showed better adhesion and proliferation than those on Ti samples.High content and small size of sp² domains were more beneficial to the adhesion,migration and proliferation of HGFs on the sample surfaces.This may be due to the formation of?-?stacking between the sp² domains of GO and the aromatic structure of protein molecules,which can improve the protein adsorption capacity of sample surfaces,and then regulate the behaviors of HGFs.?2?Magnesium?Mg?and zinc?Zn?were introduced into the surface of Ti substrate by plasma immersion ion implantation?PIII?.Compared with singly ion-implanted samples,Mg/Zn co-implanted samples released more Mg²⁺but less Zn²⁺.In vitro experiments showed that Mg/Zn ion implantation could promote HGFs adhesion,spreading,migration,proliferation and related gene expressions.Mg²⁺stimulated the expression of ITGB1,activated FAK/MAPK signaling pathway,regulated the secretion of extracellular matrix,and improved cell adhesion,spreading and migration.Zn²⁺could regulate the function of zinc transporters such as ZIP13 and ZIP7,stimulate TGF-?/Smad pathway and promote cell proliferation.Mg/Zn co-implantation not only improved the migration of HGFs,but also promoted their proliferation on sample surfaces,which were conducive to the integration of Ti implants and oral soft tissue.?3?Zn was doped into the surface of Ti samples by PIII and existed in the forms of metallic and oxidized states in the modified layer.With the extension of implantation time,the content of Zn and Zn O in the modified layer increased.Metallic and oxidized Zn on sample surfaces had different effects on the physicochemical properties of samples,jointly regulating the release of Zn²⁺.Biological characterization showed that the released Zn²⁺could promote the proliferation of HGFs,but there was a threshold of Zn²⁺concentration since extremely high concentration of Zn²⁺might reduce their promotion on cell behaviors.?4?The surface modification of Ti substrate with graphene derivatives and Mg/Zn ions was conducted by electrophoretic deposition.In vitro experiments showed that the sp² domains of graphene derivatives could improve the protein adsorption capacity of sample surfaces and Mg/Zn ions could stimulate related gene expressions and signal pathways of HGFs.It realized regulating HGFs adhesion,proliferation,migration and related gene expressions from both sample surfaces and microenvironment.