Development of a hydroxyl radical ratiometric nanoprobe

A hydroxyl radical nanoprobe has been developed by covalently attaching coumarin-3-carboxylic acid (CCA) to amine-functionalized polyacrylamide (AFPA) nanoparticles (40–100 nm in size). CCA is a non-fluorescent aromatic compound that reacts with hydroxyl radical (OH) to produce a fluorescent product, 7-hydroxy-CCA (7-OH-CCA). Texas Red-Dextran (a reference dye) is encapsulated within the nanoprobe matrix to allow for ratiometric measurements to be made that correct for variations in source intensity, sample and instrument geometry and dilution.