RESUMO
Superparamagnetic iron oxide nanoparticles, Fe(3)O(4) and gamma-Fe(2)O(3), were produced by the so-called polyol process. In order to stabilize the particles in a physiological environment as potential contrast agents for Magnetic Resonance Imaging (MRI), the as-prepared particles were successfully transferred to an aqueous medium through ligand exchange chemistry of the adsorbed polyol species with the dopamine or the catechaldehyde. The ligands were able to participate in bidentate binding to the nanoparticles surface and to improve the stability of aqueous suspensions of the nanoparticles. Analysis was performed by various techniques including X-ray diffraction, transmission electron microscopy, infrared spectroscopy and thermal analysis. The results of magnetic measurements and initial in vitro magnetic resonance imaging essays are presented for the pre- and post-surface modified nanoparticles, respectively and discussed in relation with their structure and microstructure.
Assuntos
Catecóis/química , Meios de Contraste/química , Compostos Férricos/química , Óxido Ferroso-Férrico/química , Imageamento por Ressonância Magnética , Nanopartículas/química , Benzaldeídos/química , Varredura Diferencial de Calorimetria , Coloides/química , Meios de Contraste/síntese química , Dopamina/química , Etilenoglicóis/química , Compostos Férricos/síntese química , Óxido Ferroso-Férrico/síntese química , Luz , Magnetismo , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Espalhamento de Radiação , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Titulometria , Difração de Raios XRESUMO
Chemical preparation, infrared and Raman spectra of sodium samarium fluorosilicate, NaSmSiO(4).0.25NaF are presented. The spectra are analyzed with regard to the symmetry, and the numbers of the SiO(4)(4-) internal vibrational modes observed in the Raman and infrared spectra are consistent with the predictions.
