Preparation And Cytological Studies On Collagen/Nano-hydroxyapatite/Graphene Oxide Composites

In bone tissue engineering,composite materials with three-dimensional pore,remarkable biocompatibility and appropriate mechanical properties,is one of the important direction in bone defect repair.In this study,we chose collagen(COL),one of the main compositions of natural bone,as substrate to prepared two kinds of COL/Nano-hydroxyapatite(nHA)/grapheme oxide(GO)composites:combination with nHA/GO and in-situ mineralization with GO,which combined the excellent performance of ingredients together.Materials were cultured with osteoblasts in vitro to explore their application prospect in bone repair and provide a new way for the further development of effective artificial bone repairing materials.Main content and results of this study are as follows:GO was synthesised using improved Hummers method and characterized by Scanning electron microscope(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and gravitational thermal analysis(TGA).Results showed that:(1)GO was transparent sheet with smooth surface.(2)GO was stripped into single layers whose spacing was 0.783 nm.(3)The GO dispersed well and had good thermal stability with thermal decomposition rate of 62.6%at 800℃.COL,n-HA and GO were taken as raw materials to prepare COL/n-HA/GO hybrid scaffold materials by blending,cross-linking and lyophilizing process.And then,a detailed structural,morphological and morphological characterization of the scaffold materials with different ration of GO was performed.From the result,we can found that:(1)materials showed a 3-dimensional porous structure with porosity over 90%.The holes interpenetrated well and were covered with dispersed n-HA on the wall.(2)Within certain limits,with the increasing content of GO,composites showed improved hydrophilic,mechanical properties and thermal stability.Maximum tensile strength of composites with GO 4 wt%reached at 1.28 MPa which is 42.2%higher than composites with GO 1 wt%.(3)Osteoblasts adhered and proliferated well in materials,which introduced the excellent biocompatibility of materials.COL/GO composites were immersed in simulated body fluid(1.5×SBF)for biomimetic mineralized COL/nHA/GO.Followings were the characterization and cytological experiments of the mineralized materials.We found that:(1)SEM clearly demonstrated the n-HA particles on the surface and pore-well of materials.(2)XPS,EDX spectrums and XRD patterns exhibited significant Ca and P peaks which can be attributed to the contribution of HA.(3)Antibacterial assay of the composites showed certain inhibition of the S.aureus bacterial growth.(4)Materials after mineralization exhibited no cytotoxic effect on osteoblast,showing remarkable biocompatibility.In summary,the COL/n-HA/GO and mineralized COL/nHA/GO composite materials both exhibited remarkable physical and chemical properties and biocompatibility,showing potential capacity of being promising scaffold material for bone repair tissue engineering.