The proposed invention describes methods of producing, in one pot, iron oxide nanoparticles of total diameter less than 10 nm bearing a stabilizing shell of zwitterion and associated compositions. The synthesis of zwitterated iron oxide nanoparticles was achieved by a modified Massart method by the addition of sulfobetaine siloxane either post-synthesis or before co-precipitation of iron salts (in situ). The particles are precipitated in the presence of a zwitterion siloxane which caps the particles and stabilizes them as soon as they are made.
This fine tuning finds mass applications in data storage, catalysis, and in biotechnology and medicine. Detection, cell sorting, and diagnosis using iron oxide nanoparticles have been reported. However, their potential use as contrast agents in magnetic resonance imaging (MRI) or as magnetic fluids for hyperthermia treatment continues to be the driving force for their miniaturization and surface chemistry manipulation. The particles obtained using this new method are super stable and small enough to be excreted so that they do not remain in circulation after the imaging is finished.
