Colloidal dispersion of magnetic nanoparticles without (left) and with (right) application of a magnet. Iron oxide magnetic nanoparticles of controlled sizes. The Magnetic Nanoparticles team. Colloidal dispersion of magnetic nanoparticles without (left) and with (right) application of a magnet. Iron oxide magnetic nanoparticles of controlled sizes. The Magnetic Nanoparticles team.