Eco-Friendly Synthesis of Fe3O4 Nanoparticles Based on Natural Stabilizers and Their Antibacterial Applications

Spinel magnetite (Fe3O4) nanoparticles (MNPs) were successfully synthesized from the reduction of stoichiometric ratio of aqueous solutions of Fe2+ and Fe3+ with NaOH solution. Then naturally available Ipomoea aquatica leaf aqueous extract (IA extract) was used for the surface modification of MNPs where biomolecules of leaf extract were acted as stabilizer. Gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared (FT-IR), and energy dispersive X-ray (EDX) analyses evidence the proper incorporation of the biomolecules of leaf extract in MNPs. X-ray diffraction (XRD) confirms the synthesis of MNPs where the uniform size distribution with spherical shape was approved by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses. Thermal analysis was performed using differential scanning caloremetry (DSC) and thermogravimetric analysis (TGA) and a phase transition from Fe3O4 to maghemite (gamma-Fe2O3) was detected at 650 degrees C. The superparamagnetic nature of the studied materials at room temperature was confirmed by vibrating sample magnetometer (VSM) study and the correlation among saturation magnetization (M-s), crystallite size (D), particle size (d), dislocation density (delta), and microstrain (epsilon) were described. The antibacterial activity of the synthesized MNPs was confirmed by investigating the zones of inhibition which were 19 mm for Gram-negative bacteria Escherichia coli and 14 mm for Gram-positive bacteria Bacillus subtilis.