The invention relates to colloidal sized particles composed of magnetic iron oxide (Fe.sub.3 O.sub.4) coated with a polysaccharide, preferably dextran, or a derivative thereof having pendant functional groups. The particles have a magnetic moment, are electron dense, and are stable and non-aggregating...http://www.google.fr/patents/US4452773?utm_source=gb-gplus-shareBrevet US4452773 - Magnetic iron-dextran microspheres
