Figure 1: Multifunctional imaging/therapeutic magnetic nanoparticles (MNP) anatomy and potential mechanisms of action at the cellular level [4]. (A) A multifunctional MNP modified with targeting ligands extended from MNP surface with polymeric extenders, imaging reporters (optical, radio, magnetic), and potential therapeutic payloads (gene, radio, chemo). (B) Four possible modes of action for various therapeutic agents; a) Specific MNP binding to cell surface receptors (i.e. enzymes/ proteins) facilitate their internalization and/or inactivation, b) controlled intercellular release of chemotherapeutics; c) release of gene therapeutic materials post endosomal escape and subsequent targeting of nucleus; and d) intracellular decay of radioactive materials. Reproduced with permission from Elsevier B.V.