| The repair of large segmental bone defect is still a challenge in today’s clinical routine.The most common therapeutic approach is autologous bone graft transplant,which has been proved to have effective bone repair abilities.However,there are also some disadvantages to restrict its more widespread application,such as the limited source of autologous bone and the additional damage to patients.With the development of tissue engineering and regenerative medicine,bone tissue engineering has shown promising prospects for large segmental bone repair.A porous scaffold serving as a substrate for three-dimensional tissue formation and growth factor delivery,has always been a research hotpot in tissue engineering.For the application of large maxillofacial bone defects,the scaffolds should possess good biocompatibility,as well as strong mechanical strength to resist bearing stress and support tissue regeneration.In our previous study,we successfully fabricated a three-dimensional(3D)nano-zirconia(ZrO2)scaffold with considerable mechanical strength and suitable porosity,which made it a promising scaffold for bone tissue engineering.However,as an inert bioceramic,ZrO2 shows poor toughness,high brittleness as well as limited affinity with cells and surrounded tissues.Graphene oxide(GO),an oxidized derivative of graphene,holds promise for tissue engineering application owing mainly to its unique physicochemical properties and excellent biocompatibility.With enrich oxygen-containing groups,GO sheets provide active binding sites for biological interactions and effects,and allow further functionalization.Therefore,modifying ZrO2 with GO coating could provide better mechanical properties and more feasible biocompatibility.Based on our previous research,we synthesized a 3D GO coated ZrO2 scaffold via a silane-mediated dip-coating method in this study.The surface coating with GO improved biomechanical properties of the scaffold,which can satisfy the demand of repairing maxillofacial bone defect.Furthermore,the unique surface characteristics of GO could facilitate binding of growth factors,favoring stem cell attachment,proliferation,metabolism and differentiation.This GO coating approach could offer a powerful platform for tissue engineering applications.ObjectivesThe aim of this study was to evaluate the effect of GO substrate on the attachment,proliferation and osteogenesis differentiation of human dental pulp stem cells(hDPSCs).By modifying GO on the surface of zirconia scaffold,we intended to design a GO-coated composite scaffold with excellent physicochemical properties and active biological activities to satisfy the demand of repairing maxillofacial bone defect.MethodsGO was synthesized by a modified Hummers method and then was coated on 2D glass and 3D ZrO2 scaffold via a silane-mediated dip-coating method.Surface characterization was conducted by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,and contact angle measurement.The physical and mechanical properties of GO-coated and non-coated ZrO2 scaffolds were also tested including pore size,density,porosity,compressive strength,elastic modulus.Cellular behaviors of hDPSCs including adhesion,proliferation,and osteogenic differentiation were observed to determine the biological performance of GO coating in vitro.ResultsGO possess abundant oxygen-containing groups including of hydroxyl,carbonyl,carboxyl and epoxide groups.GO coating of 2D glass significantly decreased the contact angle.GO coating significantly increased the compressive strength and elastic modulus of 3D ZrO2 scaffold without changing its pore size and porosity.GO coating on 2D glass and 3D ZrO2 scaffold provided better adhesion strength and enhanced proliferation of hDPSCs.There was more widespread and greater mineralization was observed in hDPSCs related to GO coating.ConclusionSurface modification with GO improved mechanical properties and positively modulated cellular behaviors of stem cells,indicating a promising application in bone tissue engineering. |
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