The organic layer is about 6 nm thickness and the hydrodynamic size is abouy 12-14 nm larger than their inorganic core size measured by TEM. Also Absolute Mag™ PEG Coated Iron Oxide Nanoparticles are expected to have high colloidal stability. They are stable in most buffer solutions with a pH ranges from 4-10, also they can survive autoclaving process (121°C for 30 min).