Nanohybrid composed of graphene oxide functionalized with sodium hyaluronate accelerates bone healing in the tibia of rats.

This study synthesized and characterized a nanohybrid composed of graphene oxide (GO) functionalized with sodium hyaluronate (HY) (GO-HY), evaluated its effect in vitro and determined its osteogenic potential in vivo. The synthesized nanohybrid was analyzed by Scanning electron microscopy (SEM), Raman spectrometry, Thermogravimetry, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction. MC3T3-E1 cell viability was assessed by MTT assay in 48 and 72 h. Bone defects were created in tibia of 40 Wistar rats and filled with blood clot (control), 1% HY, GO (50, 100 and 200 µg/mL) and the nanohybrid (50, 100 and 200 µg/mL). After 7 and 14 days, histomorphometric analysis was carried out to assess osteogenic potential of the nanohybrid. Immunohistochemical analysis evaluated the expression of vascular endothelial growth factor (VEGF) in bone defects. Thermogravimetric analysis, Raman and FTIR spectrometry confirmed the functionalization of GO with HY by covalent bonds. Five µg/mL concentrations of the nanohybrid did not alter the viability of the MC3T3-E1 cells. Histomorphometric analysis demonstrated that the nanohybrid at 100 µg/mL significantly accelerated the bone repair in tibia of rats when compared to controls (p < 0.01). Immunohistochemical analysis showed a significantly less intense VEGF expression in tibia treated with the nanohybrid when compared to controls (p < 0.05). The nanohybrid composed of GO functionalized with HY was able to induce the acceleration of the tissue regeneration process in bone defects created in the tibia of rats. This novel nanohybrid is a promising material for the field of bone tissue engineering.

Carbon nanotubes functionalized with sodium hyaluronate: Sterilization, osteogenic capacity and renal function analysis.

AIM: This study determined the optimum gamma irradiation dosage to sterilize sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT) and CNT functionalized with HY (HY-SWCNT and HY-MWCNT), evaluated the structural integrity of the materials and assessed whether sterilized materials kept biological properties without affecting renal function. MAIN METHODS: Materials were submitted to dosages of 100 gγ to 30 Kgγ and plated onto agar mediums for colony forming units (CFUs) counting. Sterilized samples were inoculated with 107Bacillus clausii, submitted again to gamma irradiation, and plated in agar mediums for CFUs counting. Scanning electron microscope was used for structural evaluation of sterilized materials. Tooth sockets of rats were treated with sterilized materials for bone formation assessment and renal function of the animals was analyzed. KEY FINDINGS: The optimum gamma dosage for sterilization was 250 gγ for HY and 2.5 Kgγ for the other materials without meaningful structural changes. Sterilized materials significantly increased bone formation (p < 0.05) and they did not compromise renal function and structure. SIGNIFICANCE: Gamma irradiation efficiently sterilized HY, SWCNT, MWCNT, HY-SWCNT and HY-MWCNT without affecting structural aspects while maintaining their desirable biological properties.