New opportunities in the preparation of nanocomposites for biomedical applications: revised mechanosynthesis of magnetite–silica nanocomposites

Environmentally friendly preparation of functionalized magnetite-silica (Fe₃O₄/SiO₂) nanocomposites (NCs) with different SiO₂ content (6, 20 and 50 wt%) using revised mechanosynthesis is reported. High-energy ball milling of α -Fe₂O₃, Si and SiO₂ mixtures was followed by hydrolysis and condensation of 3-aminopropyl-triethoxysilane. X-ray powder diffraction and transmission electron microscopy showed the formation of almost spherical Fe₃O₄ nanocrystals with a narrow size distribution (4–6 nm) uniformly dispersed in the amorphous 100–200 nm SiO₂ agglomerates. Scanning electron microscopy and energy dispersive spectroscopy were used to study the elemental distribution in the sample. Fourier transform infrared spectroscopy confirmed the NC surface functionalization with amino groups. Magnetic properties were also explored, indicating a homogeneous distribution of magnetic nanoparticles in the silica matrix. (paper)