Fabrication, Characterization and Osteoblast Response of Cobalt-Based Alloy/Nano Bioactive Glass Composites

In this work, cobalt-based alloy/ nano bioactive glass (NBG) composites with 10, 15 and 20 wt% NBG were prepared and their bioactivity after immersion in simulated body fluid (SBF) for 1 to 4 weeks was studied. The scanning electron microscopy images of two- step sintered composites revealed a relatively dense microstructure the density of which decreased with the increase in the NBG amount. Microstructural analysis as well as energy dispersive X-ray analysis (EDX) revealed that after 1 week of immersion in SBF, a small amount of calcium phosphate phases precipitates on the surface of the composite samples. After 2 weeks of immersion, a considerable amount of cauliflower-like shaped precipitations was observed on the surface of composites. The observed peaks in the Fourier transform infrared (FTIR) spectroscopy of the composite samples in SBF immersed for 4 weeks were assigned to hydroxyapatite. Therefore, a hydroxyapatite layer has been possibly formed on the surface of the composite samples during immersion in SBF. Cell culture results indicate that unlike the Co-based alloy, the Co-based/NBG composites are bioactive and bone cells could be vivid and grow on their surfaces, promising their possibility for implant applications.