A highly selective fluorescent nanoprobe based on AIE and ESIPT for imaging hydrogen sulfide in live cells and zebrafishElectronic supplementary information (ESI) available: Synthesis procedures, 1H NMR spectra, mass spectra, absorption spectrum, AIE behaviour, fluorescence spectra, detection limit, effect of pH, reaction mechanism and cell viability. See DOI: 10.1039/c6qm00223d

The rational design of effective tools capable of monitoring hydrogen sulfide (H 2 S) is of great importance to fully understand its physiological and pathological functions. Herein, a self-assembled fluorescent nanoprobe with both aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics for H 2 S detection has been successfully developed via a modified nanoprecipitation method. The nanoprobe features high water dispersibility, a large Stokes shift ( ca. 100 nm), good biocompatibility as well as high selectivity towards H 2 S over other putative interferents. Live cell imaging experiments demonstrate that the nanoprobe, with good cell-membrane permeability, can facilitate the visualization of exogenous and endogenous H 2 S levels. Moreover, the nanoprobe has also been found capable of detecting H 2 S in zebrafish. This nanoprobe with AIE and ESIPT characteristics can provide a novel method for the development of fluorescent probes for monitoring biological processes. An AIE/ESIPT-based nanoprobe has been developed for the specific detection and imaging of H 2 S in vitro and in vivo .