Preparation and Characterization of Superparamagnetic Iron Oxide Nanoparticles (Fe3O4) for Biological Applications

Superparamagnetic iron oxide nanoparticles (SPIONs) are developed considering the importance of this class of in different fields of biochemical and biomedical applications owing to their distinctive chemical and physical properties. In this work, the preparation of iron oxide nanoparticles (SPIONs (using Co-precipitation method has been done as the most commonly used wet chemical method of magnetic nanoparticles preparation for biological applications. The SPIONs synthesis was based on sodium hydroxide (NaOH) mediated precipitation of Fe3+ and Fe2+ salts in an aqueous solution using trisodium citrate as surfactant within a closed system. The size and stability of the magnetite nanoparticles were carefully controlled using different chemical and physical parameters in order to obtain the SPIONs with small particle size and distribution that is needed for biomedical applications. The synthesized Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and Zeta potential analysis (Zp). XRD pattern showed the presence of peaks corresponding to the phase of magnetite Fe3O4. Moreover, SEM and TEM results revealed spherical particles with a mean diameter of ≥ 5 nm. The monodispersed SPIONs were successfully prepared with a mean hydrodynamic size of 209.32 nm at a stirring speed of 900 rpm and NaOH concentration of 1.2 gm. The results showed that the particle size is considerably dependent on the stirring rate and NaOH concentration. Fe3O4 nanoparticles exhibited superparamagnetic behavior and the saturation magnetization was around 50 emu/g.