Perylenebisimide-linked nitroxide for the detection of hydroxyl radicals

A new type of fluorophore-linked nitroxide for the detection of hydroxyl radical (OH) was synthesized using perylene-3,4,9,10-tetracarboxyl bisimide and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). This new fluorescent probe, indicated here as Spy-OH (swallow-tailed perylene derivative for detecting OH) has its natural fluorescence effectively reduced due to the quenching caused by the presence of the nitroxide radical in its structure. In the presence of OH, in media containing DMSO, a conspicuous increase in the fluorescence intensity was observed. No significant change in the fluorescence intensity was observed upon the addition of other several reactive oxygen species (ROS) except for OH. Spy-OH maxima excitation (λexc) and emission (λem) wavelengths lie in the visible region (520/530 nm), therefore, this fluorescent probe is expected to be useful for a simple and selective detection of OH, especially for biosamples.