Preparation And Characterization Of Chitosan/β-Glycerophosphate Scaffolds Modified By Reduced Graphene Oxide For Bone Tissue Engineering

As a common disease,the alveolar bone defect can cause a series of maxillofacial diseases.Among the current methods of repairing bone defects,the amount of autologous bone grafts is insufficient;allograft or xenogeneic bone grafts often have postoperative rejection reactions.Therefore,for the better repairation of alveolar bone defects,well-sourced,low-cost,and biological compatible bone tissue engineering materials are imminent.Biopolymers have a wide range of sources such as good biocompatibility,degradability,and strong plasticity.As a kind of polysaccharide,chitosan(CS)not only has the above-mentioned advantages but can also simulate the structure of the extracellular matrix(ECM)and improve the osseointegration.However,the disadvantage of CS is its low mechanical strength.Hence,the combination of nanomaterials and CS is often used to improve its mechanical properties and further optimize the composite material.Reduced Graphene Oxide(rGO),as a kind of carbon-based nanomaterials,is reduced from graphene oxide(GO).It has a large specific surface area and excellent physical and chemical properties.At present,many studies have confirmed that rGO can improve the mechanical and biological properties of the original materials by synthesizing with organic polymer materials.Therefore,this study intends to prepare rGO/CS/GP bone tissue engineering scaffolds through hydrogen bonding and self-assembly of rGO and CS,and determine the optimal concentration of rGO through a series of experiments,and then further analyse the possible influence of introduction of rGO on the physical and chemical properties of the original composite scaffolds,and finally design suitable artificial scaffolds for bone regeneration.ObjectiveThis study aims to prepare rGO and modify the CS/GP scaffolds with rGO,construct the rGO/CS/GP scaffold modified with the appropriate rGO concentration,and develop suitable scaffolds for alveolar bone defects.MethodsGO was prepared by the modified Hummers method,and rGO was prepared by the green chemical reduction method,and the rGO was characterized by SEM,TEM,FTIR,etc..Then rGO was combined into the CS/GP scaffolds with different concentrations.The optimal rGO concentration was selected through surface micro-topography observation,chemical structure analysis and related physical and chemical performance testing.Finally,hDPSCs were cultured on the appropriate concentration of rGO/CS/GP scaffolds and analyzed for cell adhesion,proliferation,and osteogenic differentiation to explain the biological properties of the scaffolds.ResultsrGO has a wrinkled sheet structure and most of the oxygen-containing groups on the surface have been removed;SEM shows that the rGO sheet on the 0.25%rGO/CS/GP scafolds is uniformly bound to the trabecular surface of the chitosan-based porous scaffolds.Its pore size is approximately 113.19±46.85μm,porosity is 52.99±6.75%,water absorption is 621.48±15.99%,and the 21d degradation rate is 64.72±2.24%.The compression strength can reach to 0.29MPa when 50%deformation occurs and elastic modulus is 1.47±0.21MPa.At the time of 16h,the inoculation rate of hDPSCs cultured on the 0.25%rGO/CS/GP scaffolds was 83.22%.The MTS results on the 5th and 7th days were significantly higher than the control group,and the ALP activity of 14 days of osteogenic induction was also higher than the control group.ConclusionsThe rGO was successfully prepared by chemical reduction reaction,and the rGO was successfully combined into the CS/GP scaffolds.By comparing the physical and chemical properties of each group of scaffolds,this study believes that the 0.25%rGO on chitosan-based bone tissue scaffolds can not only obviously optimize their mechanical properties and the water absorption rate,reduce the degradation rate,but also significantly improve the cell adhesion rate,cell proliferation and cell differentiation of hDPSCs,showing great potential in the field of bone tissue engineering.