Investigate the biological activities of Lawsonia inermis extract synthesized from TiO2 doped graphene oxide nanoparticles

Nanoparticles of titanium dioxide (TiO₂) were made by reacting graphene oxide (GO) with Lawsonia inermis leaf extract. X-ray diffraction (XRD) analysis revealed crystalline TiO₂ doped GO nanoparticles composed of a variety of anatase phases. Initially, UV–vis spectroscopy was performed to confirm the biogenesis of TiO₂ doped GO nanoparticles (NP's). Using SEM, the research showed that the biosynthesized TiO₂ nanoparticles were mostly spherical, polydispersed, and of a nanoscale size. Because of the energy dispersive X-ray spectroscopy (EDS) pattern, distinct and robust peaks of titanium (Ti) and oxygen (O) were observed, which were supportive of the formation of TiO₂ nanoparticles. By using fourier transform infrared (FTIR) spectroscopy, it was demonstrated that terpenoids, flavonoids, and proteins are involved in the biosynthesis and production of TiO₂ doped GO nanoparticles. 2,2-diphenylpicrylhydrazyl (DPPH) assays were conducted to evaluate the free radical scavenging activity of TiO₂ doped GO nanoparticles. Additionally, the TiO₂ doped GO NPs had enhanced antioxidant activity when compared with the TiO₂ matrix. A series of pure TiO₂ and TiO₂ doped GO nanoparticles (5, 10, 50, and 100 mg/mL) solutions were investigated for their antibacterial activities. In the current study, zebrafish embryos exposed to pure TiO₂ and TiO₂ doped GO nanoparticles were toxic and suffered a low survival rate based on concentration. During photocatalysis, O₂˙ and ˙OH radicals are rapidly produced because of the reactive species trapping experiment. It was estimated that pure TiO₂ nanoparticles and those doped with GO were 80% effective in degrading methyl orange(MO) after 120 min, respectively.

Research Highlights

• The UV–vis absorption spectra showed a maximum absorbance peak at 290 nm.
• SEM, the pure TiO₂ doped GO NPs exhibit agglomeration and spherical shape.
• When tested in zebrafish embryos, TiO₂ NPs are toxic at high concentrations.
• GO nanoparticles showed better antioxidant activity.
• NPs exhibited concentration dependent antioxidative activity.