Super-paramagnetic iron oxide nanoparticles (SPIONs): Greener synthesis using Stevia plant and evaluation of its antioxidant properties

The super-paramagnetic iron oxide nanoparticles (SPIONs) were synthesized using an environmentally friendly method. The SPIONs with mainly carbohydrate coatings were simply synthesized using a natural, zero calorie sweetener (Stevia) extract (as both reducing and stabilizing agents). The resulting SPIONs were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HRTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), vibrating-sample magnetometer (VSM) and Zeta potential test. The SPIONs (smaller than 25 nm) are very stable due to bio-molecular coating because having a zeta potential of −41.1 mV creates opposing forces between nanoparticles and prevents them from gathering. The biogenic SPIONs were able to counteract the effects of oxidative metabolites as studied with the antioxidant activity with an IC50 of 65 μg/ml. This feature shows the capability of these nanoparticles in designing potential biomedical applications.