The Green Synthesis, Characterization and Evaluation of Antioxidant and Antimicrobial Efficacy of Silver and Gold Nanospheres Synthesized Using Wheat Bran

Objective: In the present scenario, biogenic production of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) has evoked considerable interest in terms of their diverse biomedical applications because of their extremely small size and large surface to volume ratio. Hence, the aims of the current study were to use the plant extract for the biosynthesis of AgNPs and AuNPs and to evaluate their antibacterial and antioxidant activity in vitro. Methods: First, aqueous silver nitrate and chloroauric acid solutions have been treated with wheat bran extract; a reduction of the silver nitrate and chloroaurate ions is witnessed resulting in the formation of highly stable AgNPs and AuNPs in solution. Characterization of synthesized silver and gold nanospheres is made using ultraviolet visible (UV-VIS), scanning electron microscopy, and transmission electron microscopy analysis. The free radical scavenging potential has been also investigated using 2,2-diphenylpicrylhydrazyl (DPPH) assay, examined by a UV-VIS spectrophotometer. Antimicrobial efficacy against dental disease-causing pathogens Staphylococcus aureus (microbial type culture collection [MTCC] 7443) and Streptococcus mutans (MTCC 497) was tested using agar diffusion method. Results and Conclusion: Characterization of silver and gold nanospheres indicated that they ranged from 30-55 nm to 45-70 nm in size, respectively. The synthesized AgNPs and AuNPs efficiently inhibited the growth of respective pathogens. It is found that AgNPs and AuNPs exhibited exceptionally effective antimicrobial potential-compared to wheat bran extract alone. In DPPH scavenging activity, the percentage of inhibition increases with increase in the concentration of synthesized Ag and Au NPs proved that synthesized NPs possessed high antioxidant activity. It could be concluded that these nanospheres can be act as a potent antioxidant and antimicrobial agents for commercial application.