Sintese e caracterização de nanoparticulas de oxidos de ferro para aplicações biomedicas / Synthesis and characterization of iron oxides nanoparticles for biomedical applications




In this work, morphological, structural and magnetic investigations were performed in iron oxide nanoparticles synthesized by chemical methods. Our goal was to correlate the synthesis parameters to the characteristics of the produced particles to improve their quality when compared to commercial samples and to evaluate their applicability in biomedicine. The synthetic methods were the co-precipitation of metal salts in aqueous solution and the thermal decomposition of two different organometallic precursors: iron (III) acetylacetonate (Fe(acac)3) and iron pentacarbonil (Fe(CO)5). The following techniques were used for the characterization of these systems: transmission electron microscopy, high resolution transmission electron microscopy, field emission gun scanning electron microscopy, X-ray diffraction and magnetic measurements, in addition to incorporation experiments by HeLa cells and their detection by magnetic resonance imaging. The studies showed that nanoparticles synthesized by the co-precipitation method present no advantage over the commercial samples, once they have the same broad size distribution. Through thermal decomposition of Fe(acac)3, particles with narrower size distribution were produced and positive results on their incorporation by HeLa cells and magnetic resonance imaging detection were obtained. Thermal treatments under air atmosphere were performed in the particles generated by thermal decomposition of Fe(CO)5, giving rise to crystallization, an increase of the mean diameter and stabilization of their magnetic properties, with the disadvantages of loss of the spherical shape and increase of the size dispersion. In summary, it was possible to demonstrate that thermal decomposition of organometallic compounds in hot organic solvents produces more homogeneous particles when compared with those produced by co-precipitation and commercially available ones, and this quality presents great potential for more sophisticated biomedical applications


nanomagnetismo iron oxides oxidos de ferro - aplicações biomedicas nanomagnetism nanoparticulas - aplicações biomedicas nanoparticles

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