Nowadays the use of magnetic nanoparticles (MNP) in medical applications has exceeded expectations. in molecular imaging, MNP based on iron oxide coated with appropriated materials have several applications in vitro and in vivo studies. for applications in nanobiotechnology these MNP must present some characteristics such as size smaller than 100 nanometers, high magnetization values, among others. Therefore the MNP have physical and chemical properties that are specific to certain studies which must be characterized for quality control of the nanostructured material. This study presents the synthesis and characterization of MNP of magnetite (Fe3O4) dispersible in water with perspectives in a wide range of biomedical applications. the characterization of the colloidal suspension based on MNP stated that the average diameter is (12.6 +/- 0.2) nm determined by Transmission Electron Microscopy where the MNP have the crystalline phase of magnetite ( Fe3O4) that was identified by Diffraction X-ray and confirmed by Mossbauer Spectroscopy. the blocking temperature of (89 +/- 1) K, Fe3O4 MNP property, was determined from magnetic measurements based on the Zero Field Cooled and Field Cooled methods. the hysteresis loops were measured at different temperatures below and above blocking temperature. the magnetometry determined that the MNP showed superparamagnetic behavior confirmed by ferromagnetic resonance.Instituto Israelita de Ensino e Pesquisa Albert Einstein - IIEPAEFINEPCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Hosp Israelita Albert Einstein HIAE, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Neurol & Neurocirurgia, São Paulo, BrazilFac Ciencias Med Santa Casa São Paulo FCMSCSP, São Paulo, BrazilUniv São Paulo, Inst Fisica IF, Dept Fis Aplicada, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Neurol & Neurocirurgia, São Paulo, BrazilWeb of Scienc
