Turn-on fluorescent probe based on dicyanoisophorone for bioimaging and rapid detection of peroxynitrite in aqueous media.

A novel dicyanoisophorone-based colorimetric fluorescent probe 3 has been prepared for recognizing peroxynitrite in aqueous conditions. A large bathochromic shift of the absorption band is observed upon titration with ONOO^-, inducing a clearly visible solution color change from yellow to pale pink, which makes "naked-eye" detection possible. Moreover, probe 3 can react instantly with ONOO^- and is accompanied by a significant fluorescence enhancement at 621 nm while the detection limit is as low as 37 nM. Most importantly, probe 3 exhibits high selectivity and sensitivity towards ONOO^- in the presence of other competitive ions in aqueous solution. Probe 3 has also been successfully applied in living MCF-7 cells, and the results suggest that probe 3 could be applied as a potential candidate for the detection of ONOO^-.