Antibacterial activity of biochemically capped iron oxide nanoparticles: A view towards green chemistry

Abstract A green approach to fabricate nanoparticles has been evolved as a revolutionary discipline. Eco-compatible reaction set ups, use of non-toxic materials and production of highly active biological and photocatalytic products are few benefits of this greener approach. Here, we introduce a green method to synthesize Fe oxide NPs using Punica granatum peel extract. The formation of Fe oxide NPs was optimized using different concentrations of peel extract (20 mL, 40 mL and 60 mL) to achieve small size and better morphology. The results indicate that the FeNPs, obtained using 40 mL concentration of peel extract possess the smallest size. The morphology, size and crystallinity of NPs was confirmed by implementing various techniques i.e. UV–Vis spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Electron Diffraction Spectroscopy. The bio-chemicals responsible for reduction and stabilization of FeNPs were confirmed by FT-IR analysis. The biogenic FeNPs were tested for their size dependent antibacterial activity. The biogenic FeNPs prepared in 40 mL extract concentrations exhibited strongest antibacterial activity against Pseudomonas aeruginosa i.e. 22 (± 0.5) mm than FeNPs with 20 mL and 60 mL extract concentrations i.e. 18 (± 0.4) mm and 14 (± 0.3) mm respectively. The optimized FeNPs with 40 mL peel extract are not only highly active for ROS generation but also show no hemolytic activity. Thus, FeNPs synthesized using the greener approach are found to have high antibacterial activity along with biocompatibility. This high antibacterial activity can be referred to small size and large surface area.