Synthesis of Graphene Nanoribbons–Hydroxyapatite Nanocomposite Applicable in Biomedicine and Theranostics

Abstract

In order to investigate the effect of graphene nanoribbons on the final properties of hydroxyapatite-based nanocomposites, a solvothermal method was used at 180 °C and 5 h for the synthesis of graphene nanoribbons–hydroxyapatite nanopowders by employing hydrogen gas injection. Calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as calcium and phosphate precursors, respectively. To synthesize the powders, a solvent containing diethylene glycol, anhydrous ethanol, dimethylformamide, and water was used. Graphene oxide nanoribbons were synthesized by chemical unzipping of carbon nanotubes under oxidative conditions. The synthesized powders were consolidated by spark plasma sintering methodat 950 °C and a pressure of 50 MPa. The powders and sintered samples were then evaluated using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, Vickers microindentation techniques, and biocompatibility assay. The findings of this study showed that the final powders synthesized by the solvothermal method had calcium to phosphate ratio of about 1.67. By adding a small amount of graphene nanoribbon (0.5%W), elastic modulus and hardness of hydroxyapatite increased dramatically. In biological experiments, the difference of hydroxyapatite effect in comparison with the nanocomposite was not significant. The findings of this study showed that graphene nanoribbons have a positive effect on the properties of hydroxyapatite, and these findings would be useful for the medical and theranostic application of this type of nanocomposites.

Development of Hydroxyapatite Coatings for Orthopaedic Implants from Colloidal Solutions: Part 2—Detailed Characterisation of the Coatings and Their Growth Mechanism

“…FFT analysis was performed on crystalline areas ( Figure 3 i). From the FFT diffractogram, we found the d-spacings of d = 0.344 nm and d = 0.284 nm correspond to the XRD peaks at 26° and 32° and correlate with the XRD data shown in Figure 2 a [ 69 , 70 ]. In Figure 3 i, strong [002] and [00 ] reflections are consistent with the XRD data.…”

Investigating the mechanical behavior of hydroxyapatite-reduced graphene oxide nanocomposite under different loading rates

“…HA is inherently brittle, has low fracture toughness and low wear resistance despite its excellent biocompatibility, bioactivity, non-toxicity and similarity to bone mineral composition. Therefore, reinforcing phases are added to eliminate mechanical weaknesses [12][13][14][15].…”

Characterization of hydroxyapatite-reduced graphene oxide nanocomposites consolidated via high frequency induction heat sintering method

“…But this minor improvement is not enough for implant applications of HA and it still needs to be improved by other methods, such as making composites with reinforcing phase [16,17]. For this purpose, carbon nanomaterials (carbon nanotube, graphene nanoribbons, and nanodiamonds), especially graphene sheets, have recently attracted a lot of attention due to their unique properties [18][19][20]. Graphene sheets, with the thickness of a carbon atom, have a honeycomb structure in which carbon atoms are bonded together with sp 2 hybrids [21][22][23].…”