An efficient and simple procedure to prepare chemically stable and partially carbon-cleaned magnetite from solid-state synthesis for clinical practices in medical oncology
Carregando...
Data
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Minas Gerais
Descrição
Tipo
Artigo de periódico
Título alternativo
Primeiro orientador
Membros da banca
Resumo
As far as medical applications for clinical diagnosis and therapy in oncology are concerned, the use of stables
magnetic nanoparticles relies on the magnetocaloric response of their ferrofluid suspensions to an applied
alternating current magnetic field. To assure their effectiveness as an advanced material for such a medical
technology, some critical properties, as any tendency of the nanoparticles to self-agglomerate and of the mag-
netic core component to somehow change their chemical nature, must be rigorously inhibited. A sample of
chemically stable nanoparticles of magnetite ( Fe3+
2 Fe2+O2
4 ) was synthesized through the method consisting of
burning a synthetic commercial maghemite (γFe3+
2 O2
3 ) with admixed sucrose, to partially reduce Fe3+ → Fe2+.
The residual carbon, formed on burning the sucrose, tends to coat the nanoparticles and acts as a protective layer
hindering the freshly synthesized hot magnetite from being promptly re-oxidized, on cooling the sample in the
open-air atmosphere. As a drawback, this carbon layer tends to be a thermal insulator and must be removed, in
order to make the magnetite nanoparticles able to be used as a magnetocaloric material and dissipate heat. A
chemically gentle removal of the residual carbon was assayed by treating the sample with H2O2 under stirring or
sonication either for 30 min or 60 min. The intrinsic atomic and crystalline structures and other essential
properties of this core-shell system were assessed by gas adsorption analysis (BET), powder X-ray diffraction,
Fourier-transform infrared spectrometry, M¨ossbauer spectroscopy and transmission electron microscopy. Theo-
retical analyses based on the density functional theory (DFT) were used to interpret the harmonic infrared
spectra for the produced magnetite. The efficiency in removing the residual carbon layer formed on the
magnetite grain surface was checked by saturation magnetization measurements and CHN elemental analysis.
The heat releasing ability of the prepared magnetic sample was evaluated under an AC-induced magnetic field.
These results evidenced that the treatment with H2O2 was efficient enough to remove, even though not
completely, most of the residual carbon layer, which made the saturation magnetization and the heat released by
the treated samples significantly greater than that of the untreated carbon-coated grains. The resulting nano-
magnetite was found to be a sufficiently clean material for being used for hyperthermia-based procedures,
particularly for medical diagnosis and therapy, in oncology.
Abstract
Assunto
Sacarose, Óxido de ferro, Nanopartículas magnéticas, Teoria do Funcional da Densidade
Palavras-chave
Sucrose, Iron oxide, Magnetic nanoparticle, Hyperthermic material, DFT Analysis
Citação
Departamento
Curso
Endereço externo
https://www.sciencedirect.com/science/article/pii/S2352492820326234?via%3Dihub