Synthesis and bioapplication of a highly selective and sensitive fluorescent probe for HOCl based on a phenothiazine–dicyanoisophorone conjugate with large Stokes shift

Abstract

Herein, a fluorescent probe, Dcp-EPtz, for HOCl based on a strong push–pull phenothiazine–dicyanoisophorone conjugate was prepared. The probe exhibits a very large Stokes shift of over 170 nm. Dcp-EPtz turns out to be a fast-responsive (<10 s) fluorescent probe for HOCl with high selectivity and sensitivity. It shows a good linear relationship between the enhanced fluorescence intensity at 617 nm and the concentration of hypochlorous acid in the range 0–10 μM, with the detection limit of 3.9 × 10⁻⁸ M. Moreover, the probe Dcp-EPtz exhibits the ability for endogenous HOCl monitoring in living cells.