Abstract
Bone fixation and replacement materials require a balanced combination of biocompatibility, mechanical reliability, wear resistance, and interfacial stability. In this study, a quaternary graphene oxide–hydroxyapatite–zirconia–ferrocene (GO–HAp–ZrO2–Fc) composite was developed as a bone pin material prototype using a controlled precipitation route followed by powder metallurgy processing. The composite was compacted at 400 MPa and sintered at \(800^{\circ }\hbox {C}\) to improve densification and structural integrity. Structural and physicochemical analyses using HRTEM, SAED, XRD, FTIR, Raman spectroscopy, EDX, TGA–DSC, and BET confirmed the successful integration of GO, HAp, ZrO2, and Fc into a stable multiphase nanocomposite with mesoporous surface characteristics and good thermal stability. Biological evaluation showed low cytotoxicity, with 91.13% cell viability at \(25\,\upmu \) g/mL in short-term MTT testing and 94.74% viability at \(20\,\upmu \) g/mL after extended cytocompatibility assessment. The composite also exhibited antibacterial activity against Escherichia coli and maintained cellular redox balance without inducing intracellular ROS generation in L929 fibroblast cells. Mechanical testing demonstrated a Micro-Vickers hardness of 530 HV, compressive strength of 81.2 MPa, and direct tensile strength of 92 MPa. In addition, Brazilian diametrical compression testing showed direction-dependent tensile strengths of approximately 112 MPa, 74 MPa, and 42 MPa in the longitudinal, circumferential, and radial directions, respectively, indicating bone-relevant anisotropic mechanical behavior. Tribological testing showed a low coefficient of friction in the range of 0.0738–0.102 under applied loads of 0–2 kg and sliding speeds of 50–150 rpm. Overall, the GO–HAp–ZrO2–Fc composite demonstrates a promising combination of structural stability, biological safety, mechanical compatibility, and wear resistance for further evaluation as a load-sharing bone pin material prototype, although osteoblast-specific, degradation, fatigue, and in vivo studies are required before clinical translation.
Graphical abstract