title: Nano-theranostics and Nitroxyl Radical-labeled Antitumor Agents for Magnetic Resonance Imaging.
abstract: The advent of functional contrast agents and nanoparticle drug delivery systems (nano-DDS) is opening new pathways to understanding pathophysiology using magnetic resonance imaging (MRI). Nitroxyl radical compounds are promising functional contrast agents for redox evaluation. We have developed a novel nitroxyl radical theranostic compound for noninvasive real-time imaging of blood-brain barrier-permeable antitumor drugs. Divalent manganese ions (Mn(2+)) can also be used as an intracellular functional MRI contrast agent. Manganese-enhanced MRI (MEMRI) provides a unique opportunity to study neuronal activation and architecture. Extracellular Mn(2+) can enter cells through NMDA receptors for glutamate and/or voltage-gated calcium channels. Thus, Mn(2+) can behave as a functional contrast agent depending on the cellular activity/viability. This paper summarizes the recent progress in MEMRI for neuroimaging and cancer research. Nanocarriers for DDS can contain multiple functional elements, such as therapeutic drugs, MRI contrast agents, fluorescent dyes, and radioisotopes, without significant changes in the particle kinetics/dynamics. Various materials have also been reported as nano-DDS carriers, including micelles, liposomes, dendrimers, quantum dots, and carbon materials such as fullerenes, with each material providing a different set of characteristics as a nano-DDS carrier. Our recent research into nano-DDS-based contrast agents and the theranostic applications is also outlined.
authors.affiliation: Functional and Molecular Imaging Team, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology.
authors.forename: Ichio
authors.initials: I
authors.lastname: Aoki
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging* / Q000378:metabolism*; D003287:Contrast Media; D016503:Drug Delivery Systems; D006801:Humans; D008279:Magnetic Resonance Imaging; D008345:Manganese; D059906:Neuroimaging; D009589:Nitrogen Oxides; D010084:Oxidation-Reduction; D000068936:Theranostic Nanomedicine
chemical_list: D000970:Antineoplastic Agents; D003287:Contrast Media; D009589:Nitrogen Oxides; D008345:Manganese; C039900:nitroxyl