NANOPARTÍCULAS MAGNÉTICAS FUNCIONALIZADAS COM BICAMADAS DE LAURATO/LAURATO E LAURATO/PLURONIC: ESTUDO DA ASSOCIAÇÃO COM ANFOTERICINA
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Data
2008-05-27
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Universidade Federal de Goiás
Resumo
Magnetite nanoparticles were prepared by the coprecipitation of ions Fe2+ and
Fe3+ using ammonia solution as precipitating agent. Maghemite nanoparticles
were prepared by forced oxidation of magnetite nanoparticles in acidic medium
using nitrate ions as oxidizing agent. The magnetic nanoparticles were used to the
preparation of aqueous magnetic fluids samples by the functionalization of the
nanoparticles with bilayers of laurate/laurate and laurate/Pluronic. Aliquots of the
magnetic fluids were dried and the resultant powders were characterized by
chemical analysis (the contents of ions Fe2+ and Fe3+), X-ray powder diffraction
(XRD) and Fourier transform infrared spectroscopy (FT-IR). The contents of ions
Fe2+ and Fe3+ in all the samples showed that the nanoparticles are not pure
magnetite or maghemite phases. X-ray powder diffraction (XRD) indicated the
existence of inverse cubic spinel phase, but didn't permit the distinction between
magnetite and maghemite phases. Based on the results of chemical and XRD
analyses, the nanoparticles could be better characterized as reduced maghemite,
which mean maghemite phase containing ions Fe2+. The average sizes of the
oxide nanoparticles estimated by XRD were around of 10 nm. FTIR analyses
showed that the nanoparticles were functionalized with bilayers of laurate/laurate
and laurate/Pluronic. FTIR analyses also were indicative of the maghemite phase.
The hydrodynamic size of the functionalized nanoparticles measured by PCS
were in the range of 70-90 nm for the samples based on laurate and in the range
of 100-200 nm for the samples containing Pluronic. The measurements of zeta
potential showed that the magnetic fluids based on laurate bilayers presented
better colloidal stability than that one based on bilayers of laurate/Pluronic. On the
other hand, the studies of colloidal stability in cell culture medium by hydrodynamic
size measurements showed the lost of colloidal stability of all the samples, in all
the concentrations of medium investigated. The fluids with laurate/laurate bilayers
showed higher ratio of aggregation in the culture medium than the fluids with
laurate/Pluronic. The association of amphotericin B with nanoparticles was carried
out only using the samples with laurate bilayers. The results showed that the ratio
of association depends on the concentration of amphotericin added to the
magnetic fluid. It was observed 100% of amphotericin association in the range of
nanoparticles/amphotericin concentrations used, which in turn are adequated for
posterior in vivo studies
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Citação
SILVA, Joel Rocha da. MAGNETIC NANOPARTICLES FUNCTIONALIZED WITH AMPHOTERICIN B OF
BILAYERS LAURATE/LAURATE AND LAURATE/PLURONIC: STUDY OF THE ASSOCIATION WITH
AMPHOTERICIN B. 2008. 27 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2008.