Silica/Ormosil SPIONs for Biomedical Applications
M. C. Gonçalves,
L. M. Fortes,
A. R. Pimenta,
J. C.G. Pereira,
R. M. Almeida,
M. D. Carvalho,
L. P. Ferreira,
M. M. Cruz,
In the present work, magnetic nanoparticles coated with silica or ORMOSIL are prepared in a two step process. In the first
step, SPIONs with 6 nm average diameter are produced by a reduction-precipitation process conducted in air and in the second one, SPIONs
were used as seeds for silica/ORMOSIL growth (below 30 nm), in situ by a modified Stöber sol-gel method. SPIONs and silica/
ORMOSIL magnetic core-shell nanostructures were characterized by X-Ray diffraction (XRD), Fourier transformed infrared (FTIR)
spectroscopy, transmission electron microscopy (TEM), Mössbauer spectroscopy and SQUID magnetometry. TEM observations of SPIONs
and silica/ORMOSIL SPIONs allow determining size and shape. FTIR allows determining silica/ORMOSIL structural fingerprints.
X-ray and Mössbauer spectroscopy allow determining the magnetite/maghemite ratio, discussed as a nanosized constrained. SPIONs and
silica/ORMOSIL SPIONs show superparamagnetic properties making them appropriated to biomedical applications.
Keywords: Superparamagnetic iron oxide nanoparticles, SPIONs, silica/ORMOSIL coating, sol-gel, core-shell nanostructures.
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