A ratiometric fluorescent probe for hypochlorous acid and its biological applications.

Abstract We present a lysosome-targetable and ratiometric fluorescent probe, TJ2 , for visually monitoring exogenous and endogenous HOCl in living cells by using a built-in S atom within the π-extended rhodamine fluorophore as a pH-independent recognition site. Based on the oxidation-promoted intramolecular charge transfer processes, TJ2 demonstrates fast ratiometric fluorescence response, excellent selectivity, and high sensitivity (2.3 nM) toward HOCl. Furthermore, TJ2 is highly lysosome-targetable, which could be used for ratiometric monitoring of the levels of HOCl in lysosomes. Graphical abstract A ratiometric lysosome-targetable fluorescent probe has been designed and synthesized for the sensitive and selective detection of HOCl. Image 1 Highlights • A ratiometric probe TJ2 has been synthesized for lysosomal HOCl imaging. • The probe showed fast fluorescence response, excellent selectivity, and high sensitivity (2.3 nM) toward HOCl. • The probe could be used for ratiometric monitoring of the level of lysosomal HOCl in living cells in real time. [ABSTRACT FROM AUTHOR]