Plant extract mediate synthesis of magnetite (fe3o4) nanoparticles and its antibacterial application

Abstract

Magnetite (Fe3O4) nanoparticles (NPs) were prepared through green synthesis route using Ipomoea aquatica leaf extract that acted as an efficient stabilizer and capping agent of the NPs. These NPs has potential applications in various biomedical field such as bacterial killing, targeted drug delivery, magnetic hyperthermia, magnetic resonance imaging, etc. More than 75 components including carbohydrate, lipid and polysaccharides were present in the leaf extract which was confirmed by Gas Chromatography Mass Spectrometer (GC-MS) analysis. The X-ray Diffraction (XRD) analysis showed that the particles were crystalline with cubic inverse spinel structure and the crystallite size was found to be about 12.8 ± 0.8 nm. The surface morphology of the NPs was investigated by Field Emission Scanning Electron Microscopy (FESEM) which showed that NPs were spherical in shape with uniform size distribution. Elemental analysis of the NPs was carried out with Energy Dispersive X-ray (EDX) Spectroscopy and it indicated the elemental signature of the presence of iron, oxygen, carbon and nitrogen in the NPs. The particle size was determined from Transmission Electron Microscopy (TEM) image which was about 15 nm that supported the results of XRD and FESEM. The Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that the capping agents of the NPs contained the functional groups alcohol, alkene, and alkyne. The thermal stability of Fe3O4 NPs were investigated using Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA). DSC showed two endothermic and one exothermic peaks. The percentage of weight loss was of about 10% as found from TGA. The NPs were superparamagnetic in nature with zero coercivity and zero reminance magnetization which was observed using a Vibrating Sample Magnetometer (VSM). The average particle size was determined by Dynamic Light Scattering (DLS) which showed that the particle size decreased with the decrease of precursor concentrations. This supported the results of XRD and VSM. The clear zone in the petri dish in agar diffusion test confirmed that the Ipomoea aquatica mediated Fe3O4 NPs had potential antibacterial activity for both gram negative and gram-positive bacteria. The pore formation in the bio-membrane of bacteria due to the interaction of NPs might be the possible mechanism to kill the bacteria.