Preparation and characterization of a natural composite scaffold composed of chitosan, hydroxyapatite, and graphene oxide for bone repair

The preparation of biocompatible scaffolds from natural substances for tissue engineering offers a beneficial alternative to synthetic materials for tissue repair. In this study, we prepared and characterized a composite scaffold composed of chitosan (CS), nano-hydroxyapatite (n-Hap), and graphene oxide (GO) for bone repair, and investigated its optimal composition. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) test were employed to analyze the individual components and characterize the structure, morphology, and properties of the composite scaffold. The results confirmed the successful integration of the three components, with optimal performance achieved when GO was added at a concentration of 1 wt%. GO adhered to the surface of the CS network, promoting n-Hap adsorption. As the GO content increased, the surface adsorption capacity correspondingly increased, and the scaffold exhibited superior cell growth properties and significantly enhanced compressive strength. This enables load transfer through the GO framework, inducing a nonlinear stress increase from 66.6 MPa to 243.4 MPa. At 60% deformation, the optimal compressive strength reached 53.4 MPa.Meanwhile, the degradation rate decreased linearly with increasing GO content (from 13.1% to 6.1% over 21 days), demonstrating the effectiveness of this barrier effect. This scaffold, particularly the 1.0 wt% GO formulation, demonstrated sound choice for clinical translation as a load-bearing bone defect repair material due to its mechanical strength matching that of cortical bone, a degradation rate compatible with the bone regeneration cycle, and excellent cellular compatibility. The CS/n-HAP/GO composite scaffold developed in this study achieved good performance in mechanical, degradation, and biological properties compared with previously reported similar materials, and has realized synergistic optimization of all three aspects. This formulation of three biocompatible materials provides a promising basis for fundamental bio-scaffold research and potential applications in bone repair.