Sistemas híbridos orgânico-inorgânicos contendo nanopartículas magnéticas: aplicações em hipertermia magnética e liberação controlada de fármacos
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Data
2017-02-23
Autores
Fini, Rodolfo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Neste trabalho foram preparados dispositivos híbridos ureasil-poliéter via processo sol-gel, contendo nanopartículas magnéticas (MNP) de ferrita de cobalto (CoFe2O4) ou maguemita (γ-Fe2O3), que apresentam propriedades magnéticas como superparamagnetismo, podendo ser aplicados em terapia de hipertermia e em sistemas de liberação controlada. A proposta foi sintetizar e caracterizar estes dispositivos visando a possível aplicação como agentes de liberação controlada de fármaco sob presença de um campo magnético alternado (AMF – alternated magnetic field). Assim, a combinação apropriada destas duas terapias pode proporcionar uma alternativa para eliminar células cancerígenas. Os resultados indicam que as nanopartículas de maguemita, com tamanho médio de 12 nm foram introduzidas e dispersas na matriz hibrida. A dispersão foi comprovada pelo patamar de Guinier presente nas curvas de espalhamentos de raios X a baixo ângulo (SAXS). Por outro lado, as partículas de CoFe2O4, de tamanho médio 8,7 nm, apresentaram a formação de agregados na matriz. Os valores de perda de energia específica (SLP - specific loss power) para as amostras contendo MNP evidenciam a capacidade de aplicação em hipertermia magnética. Os ensaios de liberação de fármaco foram realizados utilizando dois fármacos modelo, o diclofenaco de sódio (DCFNa) e a curcumina (CMN). A liberação de DCFNa foi monitorada a partir dos nanocompósitos carregados com maguemita, enquanto nos ensaios com curcumina foram usados para os nanocompositos de ferrita de cobalto. Nas liberações de DCFNa foi possível observar a influência da temperatura na liberação de fármaco, bem como a influência da aplicação de um AMF. A liberação de CMN se mostrou cerca de seis vezes menor para a amostra contendo CoFe2O4 em relação a amostra sem MNP, o que evidencia uma possível interação entre as nanoparticulas de ferrita de cobalto e a curcumina, indicando que a liberação pode ser modulada com a concentração de MNP de ferrita de cobalto.
In this work the sol-gel approach was used to synthesize organic inorganic hybrids loaded with magnetic nanoparticles (MNP), i.e., cobalt ferrite (CoFe2O4) or maghemite (γ-Fe2O3) which present magnetic properties such as superparamagnetism. Therefore, these materials can be used in hyperthermia therapy as well as in controlled release systems. We synthesize and characterize these devices aiming their application as agents of controlled drug delivery systems under the presence of an alternating magnetic field (AMF). Thus, the appropriate combination of these two therapies may provide an alternative to kill cancer cells. The results indicate that the maghemite particles with mean size of 12 nm were introduced and dispersed in the hybrid matrix, which good dispersion was verified by the Guinier plateau present in the small angle X-ray scattering curves (SAXS). Otherwise, the particles of CoFe2O4, 8.7 nm average size, are present as aggregates in the matrix. The values of specific loss power (SLP) for samples containing MNP make evident their capacity in magnetic hyperthermia application. Drug release assays were performed using two model drugs, sodium diclofenac (DCFNa) and curcumin (CMN). The DCFNa release was monitored from maghemite-loaded nanocomposites while for curcumin assays cobalt ferrite nanocomposites were used. The DCFNa release shows the influence of temperature on drug release, as well as the influence of the application of an AMF. The release of CMN was about six times smaller for the sample containing CoFe2O4 than that of the sample without MNP. This behavior may be due to a possible interaction between cobalt ferrite nanoparticles and curcumin, indicating that curcumin profile can be modulated by the MNP concentration.
In this work the sol-gel approach was used to synthesize organic inorganic hybrids loaded with magnetic nanoparticles (MNP), i.e., cobalt ferrite (CoFe2O4) or maghemite (γ-Fe2O3) which present magnetic properties such as superparamagnetism. Therefore, these materials can be used in hyperthermia therapy as well as in controlled release systems. We synthesize and characterize these devices aiming their application as agents of controlled drug delivery systems under the presence of an alternating magnetic field (AMF). Thus, the appropriate combination of these two therapies may provide an alternative to kill cancer cells. The results indicate that the maghemite particles with mean size of 12 nm were introduced and dispersed in the hybrid matrix, which good dispersion was verified by the Guinier plateau present in the small angle X-ray scattering curves (SAXS). Otherwise, the particles of CoFe2O4, 8.7 nm average size, are present as aggregates in the matrix. The values of specific loss power (SLP) for samples containing MNP make evident their capacity in magnetic hyperthermia application. Drug release assays were performed using two model drugs, sodium diclofenac (DCFNa) and curcumin (CMN). The DCFNa release was monitored from maghemite-loaded nanocomposites while for curcumin assays cobalt ferrite nanocomposites were used. The DCFNa release shows the influence of temperature on drug release, as well as the influence of the application of an AMF. The release of CMN was about six times smaller for the sample containing CoFe2O4 than that of the sample without MNP. This behavior may be due to a possible interaction between cobalt ferrite nanoparticles and curcumin, indicating that curcumin profile can be modulated by the MNP concentration.
Descrição
Palavras-chave
Hipertermia magnética, Liberação controlada, Nanopartículas magnéticas, Híbridos orgânico-inorgânicos, Magnetic hyperthermia, Controlled release, Magnetic nanoparticles, Organic-inorganic hybrids