Eco-friendly Synthesis of Fe₂O₃ Nanoparticles from B. variegata Extract for Combating Multidrug-Resistant Pathogens

Abstract

 This study focused on the biosynthesis of iron nanoparticles using an aqueous extract of Bauhinia Varieties as a reducing agent and stabilizer, followed by an evaluation of their antibacterial activity against several pathogenic bacterial isolates. Given the growing global challenge of antibiotic resistance, particularly in areas such as the Kurdistan Region, the search for effective therapeutic alternatives has become imperative. The nanoparticles were successfully synthesized by reacting ferric nitrate with the plant extract at pHs between 9 and 10 and temperatures between 60 and 80°C. Characterization using Fourier transform infrared spectroscopy (FTIR) confirmed this synthesis by detecting characteristic Fe-O-Fe vibrational bands at wavelengths of 576, 439, and 432 cm¹. Morphological analysis using scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the uniform spherical shape of the nanoparticles, with sizes ranging from 26 to 56nm and a homogeneous distribution. X-ray diffraction (XRD) also confirmed the formation of a pure Fe₂O₃ crystalline structure, with an average crystal size of 28.2nm. In antibacterial tests, the synthesized nanoparticles demonstrated inhibitory activity against all tested strains. The 100% concentration proved most effective against Staphylococcus aureus, showing an inhibition zone diameter of 14.3±1.1 mm. Notably, the 70% concentration showed superior activity against Staphylococcus epidermidis and Escherichia coli, with inhibition zone diameters of 15±1.1 mm and 12.67±1.3 mm, respectively. The nanoparticles reached 83.3% of the efficacy of doxycycline against Staphylococcus epidermidis, and all tested concentrations exceeded 50% of the antibiotic's efficacy against Klebsiella and Escherichia coli. These results confirm the promising potential of Bauhinia-mediated iron nanoparticles as effective antibacterial agents, especially against resistant bacteria. Further research is needed to comprehensively evaluate their toxicity, elucidate their mechanism of action, and explore their potential for synergistic applications with conventional antibiotics in future medical settings.