Silica Functionalized Magnesium Ferrite Nanocomposites for Potential Biomedical Applications: Preparation, Characterization and Enhanced Colloidal Stability Studies

Magnetic nanocomposite material composed of silica coated MgFe₂O₄ for potential biomedical applications were synthesized by a two-step chemical method including solution combustion synthesis, followed by silica coatings of the ferrite nanoparticles. The effects of silica coatings on the structural, morphological and magnetic properties were comprehensively investigated using powder X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), energy dispersive absorption x-ray (EDAX), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TG–DTA) and vibrating sample magnetometer (VSM). The colloidal behaviour of coated MNPs in physiological saline medium like water or phosphate buffer saline (PBS) was also studied by zeta potential measurements. The XRD patterns indicate that the crystalline structure is single cubic spinel phase and the spinel structure is retained after silica coating. Also, after silica coating, the crystallite size (from Scherrer formula) decreases from 53 to 47 nm. The magnetic results show that MgFe₂O₄ MNPs (bare and silica coated) is ferrimagnetic at room temperature. Zeta potential studies revealed that there is enhanced colloidal stability of MgFe₂O₄ MNPs after silica coating in aqueous media which is an applicable potential in biomedical applications.