Síntese e funcionalização de superfícies de óxido de ferro superparamagnéticos
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Data
2011-08-19
Autores
Bini, Rafael Admar [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A funcionalização de dispersões de nanopartículas superparamagnéticas de óxidos de ferro (SPIO – sigla em inglês) com moléculas bioativas, possibilita novas aplicações destes nanomateriais uma vez que a interação dos seus momentos magnéticos pode ser guiada por um campo magnético externo, o qual é dependente do revestimento da superfície das nanopartículas. Essas dispersões com propriedades superparamagnéticas podem ser utilizadas como agentes de contraste em imagem por ressonância magnética para diagnosticar tumores e doenças cardiovasculares, hipertermia na terapia do câncer e separação magnética de células e biomoléculas. Neste trabalho, nanopartículas superparamagnéticas de óxidos de ferro com tamanho entre 30 e 12 nm foram obtidas via método de coprecipitação assistida por ultrassom. Medidas de magnetização versus campo magnético mostraram comportamento superparamagnético para os óxidos de ferro sintetizados via método de sonoprecipitação química. A superfície dos SPIO sintetizados foi modificada com os reagentes 3-aminopropil-trietóxisilano (APTS), 3-aminopropil-etil-dietóxisilano (APDS) e 3-aminopropil-dietil-etóxisilano (APES). As modificações da superfície com os alcoxissilanos foram realizadas após a formação do SPIO, a qual proporcionou a modificação in situ das nanopartículas em um único passo. A funcionalização dos SPIO com ácido fólico (AF) foi realizada via método das carboidiimidas. As amostras foram caracterizadas pelas técnicas de difração de raios X, microscopia eletrônica de transmissão, espectroscopia no infravermelho com transformada de Fourier, espectroscopia no UV-Vis, mobilidade microeletroforética e espalhamento de luz dinâmico. As análises das amostras SPIO/ALCOXISSILANO/AF sintetizadas mostraram que as propriedades são dependentes...
The functionalization of superparamagnetic iron oxide (SPIO - acronym in English) nanoparticles with bioactive molecules enables new possible applications of these nanomaterials due to the fact that the interaction of their magnetic moments can be guided by an external magnetic field, which is dependent on the surface coating of nanoparticles. These dispersions with superparamagnetic properties can be used as contrast agent in magnetic resonance imaging to diagnose tumors, cardiovascular diseases for hyperthermia in cancer therapy and for magnetic separation of cells and biomolecules. In this study, superparamagnetic iron oxide nanoparticles with a size between 30 and 12 nm were obtained via the coprecipitation method assisted by ultrasound. Magnetization versus magnetic field measurements showed superparamagnetic behavior for the synthesized iron oxide by chemical sonoprecipitation method. The SPIO synthesized surface was modified with 3-aminopropyl-triethoxysilane (APTS), 3-aminopropyl-ethyl-diethoxysilane (APDS) and 3-aminopropyl-diethyl-ethoxysilane (APES). The surface modifications with alkoxysilanes were conducted after the SPIO formation, which provided an in situ modification of nanoparticles in a single step. SPIO functionalization with folic acid (FA) was performed via the carboidiimides method. The samples were characterized by techniques of X-ray diffraction, transmission electron microscopy, infrared and UV-Vis spectroscopy, microelectrophoretic mobility and dynamic light scattering. Sample analysis (SPIO/ALKOXYSILANE/FA) showed that the properties were dependent on the chemical structure of alkoxysilane used. The different molecules of alkoxysilanes resulted in different amine densities on the surface, which also influenced the content of folic acid on the nanoparticles surface. The presence of an ethyl group in the APDS molecule and... (Complete abstract click electronic access below)
The functionalization of superparamagnetic iron oxide (SPIO - acronym in English) nanoparticles with bioactive molecules enables new possible applications of these nanomaterials due to the fact that the interaction of their magnetic moments can be guided by an external magnetic field, which is dependent on the surface coating of nanoparticles. These dispersions with superparamagnetic properties can be used as contrast agent in magnetic resonance imaging to diagnose tumors, cardiovascular diseases for hyperthermia in cancer therapy and for magnetic separation of cells and biomolecules. In this study, superparamagnetic iron oxide nanoparticles with a size between 30 and 12 nm were obtained via the coprecipitation method assisted by ultrasound. Magnetization versus magnetic field measurements showed superparamagnetic behavior for the synthesized iron oxide by chemical sonoprecipitation method. The SPIO synthesized surface was modified with 3-aminopropyl-triethoxysilane (APTS), 3-aminopropyl-ethyl-diethoxysilane (APDS) and 3-aminopropyl-diethyl-ethoxysilane (APES). The surface modifications with alkoxysilanes were conducted after the SPIO formation, which provided an in situ modification of nanoparticles in a single step. SPIO functionalization with folic acid (FA) was performed via the carboidiimides method. The samples were characterized by techniques of X-ray diffraction, transmission electron microscopy, infrared and UV-Vis spectroscopy, microelectrophoretic mobility and dynamic light scattering. Sample analysis (SPIO/ALKOXYSILANE/FA) showed that the properties were dependent on the chemical structure of alkoxysilane used. The different molecules of alkoxysilanes resulted in different amine densities on the surface, which also influenced the content of folic acid on the nanoparticles surface. The presence of an ethyl group in the APDS molecule and... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Físico-química, Nanopartículas, Óxido de ferro
Como citar
BINI, Rafael Admar. Síntese e funcionalização de superfícies de óxido de ferro superparamagnéticos. 2011. 123 f. Tese (doutorado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Química de Araraquara, 2011.