Dextran Iron Oxide Nanoparticles Our water soluble dextran coated iron oxide magnetic nanoparticles (Catalog # IDX) is coated with dextran (MW 10,000). The iron oxide core in IDX has a diameter at 5 to 10 nm. IDX has a zeta potential ranging from -10mV to 0mV and a hydrodynamic size of about 25 nm. Since dextran is a natural polysaccharide that is used as an antithrombotic agent, IDX has excellent compatibility and suitability for in vivo studies. The colloidal stability of IDX is exceptionally high. It is stable in most buffer solutions (borate, Tris-HCl, PBS, MES, TAE, and TBE) and in the pH range of 3-14. It is also stable in culture media with or without FBS.