Antibacterial activity of iron oxide nanoparticles synthesized by co-precipitation technology against Bacillus cereus and Klebsiella pneumoniae

The present study investigates the synthesis and characterization of iron oxide nanoparticles (Fe₃O₄-NPs) for their antibacterial potential against Bacillus cereus and Klebsiella pneumonia by modified disc diffusion and broth agar dilution methods. DLS and XRD results revealed the average size of synthesized Fe₃O₄-NPs as 24 nm while XPS measurement exhibited the spin-orbit peak of Fe 2p_3/2 binding energy at 511 eV. Fe₃O₄-NPs inhibited the growth of K. pneumoniae and B. cereus in both liquid and soild agar media, and displayed 26 mm and 22 mm zone of inhibitions, respectively. MIC of Fe₃O₄-NPs was found to be 5 μg/mL against these strains. However, MBC for these strains was observed at 40 μg/mL concentration of Fe₃O₄-NPs for exhibiting 40–50% loss in viable bacterial cells and 80 μg/mL concentration of Fe₃O₄-NPs acted as bactericidal for causing 90–99% loss in viability. Hence, these nanoparticles can be explored for their additional antimicrobial and biomedical applications.