Exploring the antioxidant activity and cytotoxicity of the reduced graphene oxide-based nanocomposite

In the current study, the radical scavenging activity and cytotoxicity of reduced graphene oxide (rGO), mediated by titanium dioxide (TiO₂) nanocomposite, have been explored. The sol-gel method was utilized to synthesize TiO₂ nanoparticles without surfactants, and the improved Hummer's method for the graphene oxide (GO) was followed by the thermal reduction method to obtain rGO. The single-step hydrothermal process was utilized for the synthesis of GO@TiO₂ and rGO@TiO₂ nanocomposites. Fourier transform infrared spectrum, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectrum of the nanocomposites were investigated. XRD and Raman spectra confirm the anatase phase TiO₂ formation on the 2D layer of the rGO nanosheet. FESEM and HR-TEM confirmed the spherical TiO₂ with a 6.75 ± 1.42 nm diameter decorated on a 2D rGO nanosheet. The rGO@TiO₂ (91.18%) exhibited higher antioxidant properties than the GO@TiO₂ (70.00%) nanocomposite at 400 µg/mL concentration, evaluated by the DPPH method. Moreover, the nanocomposite exhibits stronger scavenger activity towards the hole scavenger than the electron scavenger. The rGO@TiO₂ nanocomposite showed less cytotoxicity towards L929 cells compared to TiO₂ nanoparticles, GO, rGO, and GO@TiO₂. The antibacterial properties of the rGO against Staphylococcus aureus bacteria were enhanced by adding TiO₂ nanoparticles. Thus, the results support the potential antioxidant properties of rGO-based nanocomposites that can be explored for biomedical and environmental applications.