Nitric Oxide Delivery Tracked By Fluorescence

A novel nitric oxide-delivering ruthenium complex can be tracked by its fluorescence as it passes through a cellular environment and drops off its NO cargo (Chem. Commun., DOI: 10.1039/b805332d). The ability to track the complex boosts its potential for photodynamic therapy in which light could be used to target the release of the cancer-cell-killing NO at specific locations, particularly under the skin. Pradip K. Mascharak and Michael J. Rose of the University of California, Santa Cruz, and colleagues developed the ruthenium nitrosyl complex containing a dansyl-imidazole fluorescent ligand that releases NO when exposed to visible light. When the complex contains NO, it fluoresces green. The release of NO quenches the fluorescence, Mascharak explains. The group tested the compound’s NO-delivering ability in human breast cancer cells and monitored NO release to the cell by the loss of fluorescence.