Hydroxyapatite and Er₂O₃ are embedded within graphene oxide nanosheets for high improvement of their hardness and biological responses

A novel nanocomposite hydroxyapatite (HAP)/Er₂O₃/graphene oxide (GO) is synthesized to be suggested for bone replacement applications. HAP/Er₂O₃/GO is analyzed with XRD, FTIR, and XPS scan to prove the uniform distribution of HAP and Er₂O₃ within the GO sheet. TEM graphs illustrate the morphological alteration that occurred upon combining HAP and Er₂O₃ with GO sheets. The ternary composite shows an average diameter of 8-16 nm and length of 20–40 nm for HAP and a diameter of 4 nm for Er₂O₃. The SEM graphs showed the uniform distribution of HAP and Er₂O₃ particles over the GO sheets with a diameter of 0.3 μm for HAP and 0.4 μm for Er₂O₃. In addition, the roughness average (Ra) of the triple nanocomposite is 9.85 ± 0.40 nm. Further, HAP/Er₂O₃/GO cell viability is 96.9 ± 1%. Furthermore, its antibacterial activity shows a maximum value of 14.9 ± 1.9 mm against E. coli and 14.4 ± 1.4 mm against S. aureus. Moreover, HAP/Er₂O₃/GO obtained the maximum value in the hardness study of 5.3 ± 0.4 GPa. Therefore, HAP/Er₂O₃/GO shows a noticeable enhancement in surface roughness and hardness parameters as well as exhibiting antibacterial properties. Besides, the improvement in cell viability consequently enhances biocompatibility and bioactivity. Hence, HAP/Er₂O₃/GO composition is a promising bone implant material for bone replacement applications. Graphical Abstract: [Figure not available: see fulltext.]