Coordination Chemistry in 19F Magnetic Resonance Imaging: Agents for Illuminating Biological Environments in Vitro and in Vivo
19F Magnetic resonance imaging (MRI) is an emerging technique for in vivo imaging, showing great promise due to the favorable NMR properties of the fluorine nucleus (high sensitivity, large ppm range) and the lack of detectable fluorine signal in biological systems. Imaging agents can be designed that exhibit either a turn-on or chemical shift response that is selective for a specific biological molecule or event. We are developing a series of metal complexes designed to report on different biological environments associated reductive stress (hypoxia), oxidative stress, changes in pH, metal ion concentration, and enzymatic activity. These sensors act via a switch from a paramagnetic to diamagnetic state upon reduction or oxidation at the metal center. Through careful tuning of the ligand scaffold, we have developed selective sensors for hypoxia and oxidative stress, showing promise for future applications for in vivo detection of these states in both cellular and animal disease models. New enhanced nanoparticle-based platforms based on metal-doped perfluorocarbons will also be discussed.