Simple and novel strategies to achieve shape and size control of magnetite nanoparticles intended for biomedical applications

Abstract

Monodisperse magnetite nanoparticles (MNPs) with controlled sizes and shapes were prepared. The synthesis was carried out by traditional and inverted co-precipitation method with some modifications such as presence of visible light, room temperature and absence of inert atmosphere. Sodium dodecyl sulphate (SDS) was employed as stabilizer. The mentioned experimental parameters were conveniently adjusted to obtain suitable MNPs, to be efficiently employed in biomedical applications. In particular the size, shape, surface charge and magnetic properties were evaluated. MNPs were thoroughly characterized. From characterization data, it emerged that the inverted co-precipitation in presence of visible light rendered mainly nanorods. Modifying the SDS concentration the shape was tuned from nanorods to nanospheres and finally, at higher concentrations, nanocubes were obtained. All prepared formulations resulted hydrophilic. This property was justified in terms of the stabilization mechanism of SDS.Stability of MNPs aqueous dispersions was evaluated regarding to the variation of hydrodynamic diameter as a function of the time. In this regard, all the formulations resulted stable during, at least, 30 days. The prepared nanosystems exhibited satisfactory magnetic properties with saturation magnetization slightly lower than raw magnetite.The combination of size, shape, surface charge, hidrophilicity and magnetic behaviour make the magnetic nanosystems here obtained highly suitable and promising to diagnostic and therapeutic applications.