A highly specific red-emitting fluorescent probe for monitoring of Cu in living cells and zebrafish.

A novel seminaphthorhodafluor-based fluorescent probe was designed and prepared. It exhibited an outstanding off-on fluorescence response (about 45-fold enhancement) to Cu because the structure changed from a spirocyclic form to a ring-open state. It showed satisfactory detection performances for Cu with fast response speed, high selectivity and anti-interference, and a low detection limit (22.9 nM) due to its long emission wavelength and off-on fluorescence response mode. This probe was also satisfactorily applied for the monitoring of Cu in living cells and zebrafish.