FIG. 1.

Simplified schematic of nanoparticles. SPIONs are nanoparticles with an iron oxide core (maghemite, magnetite, or hematite core) and are categorized by their hydrodynamic size. Transitional metal oxides (copper, cobalt, nickel, and manganese) mixed with iron oxide also exhibit superparamagnetic properties and are considered members of the SPION family. SPIONs are one of the most employed contrast agents for the labeling of cells, and serve a variety of applications such as imaging, drug delivery, magnetic hyperthermia, and others. Bare SPIONs are cytotoxic, tend to aggregate/agglomerate, and undergo further oxidation, which makes an appropriate coating crucial. Various materials are used for coating, but most SPIONs intended for medical applications are coated with biocompatible derivatives of dextran. SPION, superparamagnetic iron oxide nanoparticle. Color images available online at www.liebertpub.com/teb