Síntese e caracterização de óxidos de ferro visando sua utilização como agentes de contraste para ressonância magnética.

Abstract

Contrast agents are materials of great relevance to the quality of the images obtained by magnetic resonance imaging, accentuating the contrast of images and facilitating the diagnosis of pathologies. Nanoparticles have been widely used as contrast agents for magnetic resonance imaging, and the most used are nanoparticles of iron oxide. The safety and toxicity of nanoparticles has been the subject of increasing concern, because knowledge about the biological effects of such materials is not enough. The properties of the nanoparticles, in turn, depend on the size, microstructure and surface coating, all of them controlled by the conditions of synthesis and processing of nanoparticles. The aim of this study was to obtain iron oxide by Pechini method, for use as contrast agents in diagnostic magnetic resonance imaging, in order to characterize them. Iron oxide nanoparticles were synthesized by Pechini method with ratio of citric acid to metal cations in relation 3:1, subsequently calcined at temperatures of 400 º C and 900 º C, for periods of 1h or 2h. Soon after were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy Xray (EDS), X-Ray Diffraction - (XRD), Differential Scanning Calorimetry analysis (DSC) , Thermogravimetry (TG), and Fourier Transform Infrared Spectroscopy (FTIR). Was also performed Cytotoxicity Assay - Cell Viability. The XRD showed the formation of phase of hematite and presence of second phase of magnetite. The morphology consists of rigid aspect of agglomerates with particles of irregular shape and with a smaller size greater than 10 µm. The calcination temperature of 400 ° C was not sufficient to obtain iron oxide nanoparticles thermally stable. The powders obtained by the Pechini method showed no cell viability.