Photoswitchable AIE nanoprobe for lysosomal hydrogen sulfide detection and reversible dual-color imaging

Current lysosomal H 2 S-responsive fluorescent probes usually possess notorious aggregation caused quenching (ACQ) phenomenon and suffer from the inevitable background fluorescence signals. To circumvent this problem, we here combined H 2 S recognizing aggregation-induced emission (AIE) group with photochromic spiropyran moiety to rational design novel photoswitchable AIE nanoprobe (DNBS-DCM-SP) for lysosomal H 2 S detection with high spatiotemporal resolution. In the presence of H 2 S, the electron-withdrawing DNBS moiety will deviate from DNBS-DCM-SP via a H 2 S-induced O S bond cleavage, induced a sensitive turn-on fluorescence response at about 592 nm. The prepared nanoprobe displays good sensitivity (∼5.0 nM), and high specificity (especial against other thiols). In additon, the fluorescence of the H 2 S-activated AIE nanoprobe (DCM-SP) can be reversibly switched by selective fluorescence resonance energy transfer (FRET) from the AIE fluorophore (DCM) to ring-opened state of spiropyran via alternating UV/visible light irradiation. Moreover, the feasibility of the prepared photoswitchable AIE nanoprobe is also demonstrated by mapping the production of endogenous H 2 S in living cells as well as reversible dual-color fluorescence imaging.