Rational modulation of coumarin-hemicyanine platform based on OH substitution for higher selective detection of hypochlorite

To monitor delicate changes of biological HOCl in vivo , a new probe (OH-substituted coumarin-hemicyanine, probe 2 ) was synthesized for NIR and ratiometric HOCl detection. Selectivity studies indicated that the electron-donating group (OH) substituted on the indolium moiety enhanced the selectivity to detect HOCl. With HOCl, the probe showed a ratiometric fluorescence ( I 500 / I 650 ) with a low detection limit (49.1 nM) and a rapid response (within 2 min). In addition, probe 2 was successfully applied to visualize exogenous and endogenous HOCl in living cells and animals and exhibited a perfect mitochondria target ability. This probe has been further studied as a potential and powerful tool to probe HOCl in arthritis models. A NIR and ratiometric fluorescent probe was developed to quantitate arthritis-dependent HOCl production in vivo with high selectivity and sensitivity.