BIODISTRIBUIÇÃO DE NANOPARTÍCULAS MAGNÉTICAS UTILIZANDO CAMPO MAGNÉTICO EM RATOS

• Autor(a) principal: Paula, Valnir de
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional Universidade Franciscana
• Texto Completo: http://tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/194; http://www.tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/331
• topic: Ressonância magnética nuclear; agentes de contraste; sistema fagocitário; Magnetic resonance imaging; contrast agents; phagocyte system; CNPQ::ENGENHARIAS

The use of nanoscale products in several areas, including medicine, is a growing reality. The magnetic nanoparticles (MNPs) for being able to present a significant effect of magnetization when exposed to an external magnetic field, have been the focus of several studies, and among their applications is their use as contrast agent in magnetic resonance images. This technique provides images based on the nuclear behavior of the atoms of anatomical structures, which can be best highlighted by the use of contrast agents, usually paramagnetic. The MNPs represent an alternative to the current class of paramagnetic contrast agents for nuclear magnetic resonance, used for a long time, with advantages from a physical point of view, because they highlight even more the magnetic behavior of protons in different tissues, especially liver, spleen and lymphatic system, whose defense cells endocyte these MNPs, making healthy parenchyma dark (hyposignal), so that any injuries stand out in the images, facilitating their identification. This study has aimed to assess the contrast degree of the organs of the phagocyte system, injecting NPMs doses ranging from 0.46 to 7.2 mg/kg in rats, by caudal intravenous flow and subjecting them to nuclear magnetic resonance imaging. The MNPs was divided into two groups, both with a core of magnetite, varying the coating, which has been dextran in group 1, and oleic acid in group 2. The expected effect was that the organs of the phagocyte system would have some degree of signal loss in the images, indicating that the NPMs were internalized by the cells of these organs. With the usual contrast agent, paramagnetic, which does not enter cells, the effect is the hypersignal in the vascular system and in hypervascularized organs. We have compared the images obtained from T1 TSE and T2 TSE sequences with the control obtained before injection. The results have shown that both dextran coated MNPs and the ones coated with oleic acid have caused the hyposignal effect in the images, ranging from weak to strong, depending on the administered dose, especially in T2 TSE sequences. The dextran coated MNPs have shown higher efficiency, considering that the hyposignal effects have occurred with lowers doses, compared to the effects caused by NPMs coated with oleic acid. It can be concluded, given the evident hyposignal effect presented by the organs of the phagocyte system, the potential application of MNPs as a contrast agent in magnetic resonance studies.