Ponente
Descripción
Superparamagnetic iron oxide nanoparticles (Fe3O4) have been the subject of an intense research for their potentiality in numerous biomedical applications, especially for the diagnosis and therapy of many human diseases like cancer. This research is focused on the controlled synthesis of magnetite using gamma-radiolysis technique in an aqueous solution containing iron chloride in presence of polyvinyl alcohol as colloidal stabilizer. The solutions were irradiated with gamma-rays from a 60Co source to various absorbed doses in the range of 50 to 150 kGy, at a dose rate of 2 kGy/h.
The synthesis using nuclear technique allows minimal use of potentially harmful chemicals and simple production schemes in aqueous systems, which minimizes the use of organic solvents and the and the subsequent purification of the final products is not necessary. Besides, radiolysis involves the in-situ generation of strong reducing species homogeneously distributed in the solution, which is difficult to achieve with other chemical methods. The final size and morphology of the particles are regulated by radiolytically induced steady-state redox conditions at the water-solid particle interface and the oxide phase.
The structure, morphology and magnetic properties of the nanoparticles obtained were characterized by X Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and magnetometry techniques. The XRD studies confirm the cubic crystal structure of Fe3O4, especially at the 100 kGy dose. SEM and TEM graphics indicate that the magnetite nanoparticles are almost spherical in shape and that the particle size is lower than 20 nm. Magnetic characteristic of Fe3O4 nanoparticles was indicated superparamagnetic properties and the saturation magnetization of samples varies with increasing irradiation dose.
