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

Hassan Nosrati,Amir Hossein Ahmadi,Rasoul Sarraf-Mamoory,Maria Canillas Perez

doi:10.3390/jnt1010002

Hassan Nosrati, Amir Hossein Ahmadi + Show 2 more

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https://doi.org/10.3390/jnt1010002

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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.

Highlights

Hydroxyapatite (HA, a member of the calcium phosphate family) has poor mechanical properties
The initial solution (S1) was first prepared (DI water + Dyethylene glycol (DEG)+ Dimethyl formamide (DMF)+ anhydrous ethanol with a volume ratio of 40:20:20:20), and the following steps were performed in order. 4.7 g of calcium nitrate tetrahydrate in 120 mL of S1 was added dropwise to a 20 mL stirred suspension of graphene oxide nanoribbons (GONRs) (3.13 mg/mL) (HA/0.5% rGONR) with stirring continued for 1 h.1.56 g of diammonium hydrogenphosphate in 80 mL of S1 was dropwise added to the solution, and the pH of the resulted solution was adjusted to >10 with ammonium solution.The suspension was sonicated for 1h (Irradiation power of 140W, A QSONICAQ700 sonicator with a maximum power output of 700W was employed for the ultrasonic irradiation).The resulting solution was poured into
According to the X-ray diffraction (XRD) pattern of the synthesized powders (Figure 2a), full conformity is achieved between the reference standard of pure HA (JCPDS 09-0432) and the peaks obtained [52]

Summary

Introduction

Hydroxyapatite (HA, a member of the calcium phosphate family) has poor mechanical properties. The most important of these properties are low fracture toughness (fracture toughness of less than 1 MPa.m0.5), intrinsic brittleness, poor tensile strength, and weak wear resistance [1,2,3,4]. Despite these poor mechanical properties, HA has excellent biological properties, including bone bonding ability, excellent biocompatibility, highly compatible with living bone tissues, scaffolding properties, and osteoconductive properties [5,6,7,8,9,10]. Excellent mechanical properties, and high specific surface area has been studied more than carbon nanotubes [33,34,35,36,37,38]

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