Superior antibacterial activity of reduced graphene oxide upon decoration with iron oxide nanorods

Abstract Iron oxide (Fe2O3) nanorods (NRs) decorated reduced graphene oxide (rGO) nanocomposite, endowed with high antibacterial activity, was prepared through the one-pot calcination of pre-synthesized Fe2O3 NRs in rGO aqueous dispersion. The Fe2O3 NRs were well infused between the rGO layers as revealed by the AFM, SEM, and TGA analysis, whereas the removal and distribution of oxygen-containing functional groups were distinguished with UV–vis and FT-IR spectroscopy. The antibacterial activity of Fe2O3/rGO nanocomposite towards methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus (VRSA), and ciprofloxacin-resistant Staphylococcus aureus (CRSA) was investigated by disk diffusion method and growth curve analysis. The nanocomposite demonstrated excellent antibacterial activity as compared to bare rGO and inhibited nearly 87 % of the bacterial growth. The CRSA was more sensitive to nanocomposite compare MRSA and VRSA. More importantly, the nanocomposite obtained was found to achieve minimum inhibitory concentration (MIC) of ∼ 5 µg/mL. Besides, measurements of the charge transfer resistance, which is used to interpret bacterial response towards rGO or Fe2O3/rGO modified glassy carbon electrode, were performed using electrochemical impedance spectroscopy (EIS). The noteworthy antibacterial performance of the Fe2O3/rGO nanocomposite was probably attributed to the synergistic effect Fe2O3 NRs decorated rGO. The mechanism study suggested that nanocomposite can induce death to the bacteria by direct contact with the sharp edges of rGO and through the release of Fe3+ ions. The data, altogether, indicated that the Fe2O3 NRS decoration of rGO resulted in nanocomposite with enhanced antibacterial performance, hence, it may be used for developing new, safe, and effective antibiotics.