Exploring the antimicrobial potential of biologically synthesized zero valent iron nanoparticles

Abstract

Abstract The widespread use of antibiotics has resulted in the emergence of multidrug-resistant bacteria. Therefore, it is essential to explore alternative strategies to effectively combat medically significant resistant pathogens. In recent years, nanoparticles (NPs) have emerged as a promising alternative source of antimicrobial agents. While nanoscale particles were traditionally synthesized using chemical techniques, the development of metallic NPs using biological methods has garnered attention. This current study focuses on the synthesis of iron NPs (Fe NPs) using metal-tolerant fungal strains, as numerous microorganisms serve as environmentally safe and durable precursors to produce persistent and bi-functional NPs. The study involved the isolation and evaluation of ten fungal strains that are resistant to heavy metals to determine their ability to produce Fe NPs. The biologically synthesized Fe NPs were characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy techniques. The XRD results indicated the presence of Fe in nanopowder form, displaying a series of reflection angles (2θ) at 65° and 75° indicating the existence of cubic planes. EDX analysis revealed the presence of ferrous and ferric elements, along with zero-valent Fe NPs. Micrographs of the surface topology displayed spherical aggregation of the synthesized NPs. Furthermore, the Fe NPs exhibited promising antibacterial potential against selected bacterial strains, including Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Cronobacter sakazakii, Listeria innocua, and Enterococcus fecalis. This study demonstrates that the biological synthesis of metallic NPs is environmentally safe, and Fe NPs produced through mycological means could be utilized to combat antibiotic-resistant pathogenic strains.