Synthesis of ordered mesoporous silica containing ferrites for magnetically induced hyperthermia

Full text: Applications of magnetic nanoparticles in biomedicine have attracted great interest of the scientific community over the past decade due to its enormous potential for hyperthermia treatment. At temperature around 43°C cancer cells are destroyed due to their source of oxygen through blood vessels is not enough. Studies have shown that the magnetic properties of ferrites can be used to promote localized heating. The efficiency of cobalt ferrite, nickel ferrite and zinc ferrite nanoparticles have been compared in some studies for applications in hyperthermia. However these nanoparticles tend to agglomerate and form large clusters, leading to loss of interesting characteristics. Moreover, ferrites nanoparticles are very reactive and when exposed to magnetic field can reach high temperatures due surface effect. One way to solve this problem is disperse them in a matrix of silica such as SBA-16. Therefore, we have explored a protocol for synthesizing SiO₂-CoFe₂O₄, SiO₂-Fe₂O₄ and SiO₂-ZnFe₂O₄ nanocomposites and their AC magnetic-field-induced heating properties for cancer therapy. These materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) , N₂ adsorption, small angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The results were analyzed to confirm the formation of the nanocomposites and elucidate the physicochemical, structural and magnetic properties of the samples. Measurements of AC magnetic-field-induced heating properties of the different obtained nanocomposites under 200 and 220 Oe applied magnetic fields showed that they are suitable as hyperthermia agents for biological applications. (author)