A novel “off-on” type fluorescent chemosensor for detection of Zn2+ and its zinc complex for “on-off” fluorescent sensing of sulfide in aqueous solution, in vitro and in vivo

Abstract

We reported a new quinoline-based fluorescent probe 1 for Zn2+ and S2-. 1 showed a highly selective fluorescence enhancement toward Zn2+ over other metal ions including Cd2+, and the resulting 1-Zn2+ complex could detect only S2- among the various anions. The detection limits (0.09 mu M and 0.88 mu M) for Zn2+ and S2- were much lower than recommended values (76 mu M for Zn2+ and 14.8 mu M for S2-) by WHO. Their recognition mechanisms were explained by Job plots, UV-vis titrations, H-1 NMR titrations, ESI-mass, and theoretical calculations. Moreover, compound 1 with the great photostability and low biotoxicity showed sequentially off-on-off fluorescent bio-imaging of Zn2+ and S2- in both HeLa cells and live zebrafish larvae. (C) 2018 Elsevier B.V. All rights reserved.