Rational construction of an AIE-active fluorescent probe bearing three reaction sites for individual and continuous detection of H2S and HClO with single-wavelength excitation

Endogenous H2S and HClO play vital roles in regulating the redox status in vivo, and are involved in many pathophysiological events. Accordingly, accurate sensing and imaging of intracellular H2S and HClO have become greatly in demand. However, conventional double-response fluorescent probes for these two substances suffered from the notorious aggregation-caused quenching effect and required multiple excitations to achieve discrimination determination. In this study, we firstly constructed an AIE-active fluorescent probe with three potential reaction sites for individual and continuous detection of H2S and HClO using a single excitation wavelength. The multiple-site probe exhibited distinctive fluorescence behaviors to H2S and HClO with fast response (H2S: 12 min; HClO: 1.8 min), well-separated emission peaks (88 nm), high sensitivity and good selectivity due to H2S-induced thiolysis of 2,4-dinitrophenyl ether assisted by an adjacent aldehyde and HClO-triggered sulfur oxidation. The corresponding recognition mechanisms were fully confirmed by HRMS, 1H NMR and control experiments. Moreover, the probe was successfully utilized for separate and continuous imaging of intracellular H2S and HClO in different fluorescent channels, indicating its potential for further study the biological functions of H2S and HClO in living systems.