Facile Green Synthesis of Iron Oxide Nanoparticles Using Phoenix dactylifera L. Seed Extract and Their Antibacterial Applications

Abstract

Aim: The synthesis methods of iron oxide nanoparticles (IONPs) have got great attention in recent years, due to their variety in physicochemical properties and applications. This study aimed for the green synthesis of the IONPs using an aqueous extract of P. dactylifera L. seeds for its antibacterial applications. Methodology: IONPs were prepared in an aqueous seed extract of P. dactylifera L. The physicochemical characterisations were performed with transmission electron microscopy (TEM) to study the shape of obtained nanoparticle, energy-dispersive spectroscopy (EDS) for elemental confirmation of iron and oxygen, dynamic light scattering (DLS) for particles size measurement, vibrating sample magnetometer (VSM) for saturation magnetisation, Infrared spectroscopy (FTIR) for chemical confirmation of function groups and X-ray diffraction (XRD) for crystalline nature. The polyphenols contents were also determined; we suggest that the presence of phenolic compounds is the key element involved in the formation and the stabilisation of IONPs. Antibacterial activity was determined using disc diffusion assay and minimum inhibitory concentration (MIC) of the IONPs were determined by broth dilution assay. Results: The biosynthesised IONPs showed crystalline magnetite spherical morphologies with average diameter 30 nm. Discs with all the concentrations of IONPs tested in this study (10 - 100 ug.mL-1) showed antibacterial activity against bacterial strains tested (Staphylococcus epidermidis, Klebsiella pneumoniae and Pseudomonas aeruginosa). MIC values were found to be 30 ug.mL-1, 50 ug.mL-1 and 60 ug.mL-1 for S. epidermidis, K. pneumoniae and P. aeruginosa respectively. Conclusion: The biosynthesis of IONPs has provided, reliable, safe, simple and eco-friendly method. Hence, this study has focused on biological method of synthesis of IONPs. The IONPs synthesized in this study can be used as the therapeutic agents against bacteria.