Investigating the in vitro antibiofilm, antioxidant and photocatalytic potential of iron oxide nanoparticles biofabricated from Bauhinia variegata

Abstract

The emergence of multidrug-resistant (MDR) bacteria poses a critical challenge to modern medicine, necessitating the development of novel and effective therapeutic strategies. The present study introduces a green synthesis approach for producing iron oxide (FeO) nanoparticles using aqueous leaf extract of Bauhinia variegata L., as both reducing and stabilizing agents. Characterization confirmed the formation of highly crystalline spherical FeO nanoparticles, typically under 100 nm in diameter. The plant-derived secondary metabolites such as phenolics, tannins, and flavonoids identified via FTIR spectroscopy were confirmed to be associated with the nanoparticles, contributing to their promising biological activities. FeO nanoparticles demonstrated broad-spectrum antibacterial efficacy against a panel of clinically relevant MDR pathogens (A. baumannii, E. coli, K. pneumoniae, P. aeruginosa, E. faecium, and S. aureus), and their antibacterial potential might be attributed to the activation of reactive oxygen species (ROS) via the Fenton reaction. Furthermore, the nanoparticles exhibited significant anti-biofilm activity, inhibiting initial bacterial attachment and slime production, and achieved high levels of biofilm inhibition (69.77–79%) across all tested bacterial strains. In addition to their antibacterial potential, FeO nanoparticles showed strong antioxidant activity against DPPH, ABTS, and H₂O₂ radicals. They also displayed excellent photocatalytic degradation of Congo red dye (89% degradation), showcasing high degradation efficiency that is directly linked to their small size and high crystallinity. Findings of this study underscore the significant potential of FeO nanoparticles for biomedical and environmental applications because of their promising antibacterial, antibiofilm, antioxidant and photocatalytic actions and a greener route for the synthesis of these nanoparticles.