Novel 'naked-eye' Bis-Schiff base fluorescent chemosensors for sensitive detection of Zn2+ and bio-imaging in living cells

摘要

Novel chemosensors based on excited state intramolecular proton transfer chemosensors (F1, F3, F5) and reference dyes (F2, F4, F6) are presented in this work. Target dyes Fl, F3 and F5 display high selectivity and sensitivity toward Zn2+ in solvents (such as EtOH, EtOH/PBS buffer) in the presence of competitive ions (K+, Na+, Ni2+, Pb2+, Mn2+, Mg2+, Hg2+, Cu2+,Cd2+, Cr3+, Fe3+). Sensing property for Zn2+ was studied by UV-Visible, fluorescence spectrophotometric analyses and Job's plot analyses. F1, F3 and F5 for Zn2+ detection revealed extremely low detection limit (67.2 nM), high anti-interference ability, and the immediate response. Furthermore, inverted fluorescence microscopy imaging experiment were also investigated, the results demonstrated that the probes have well cell membrane permeability and hypotoxicity. Simultaneously, due to the ability to adapt a wider range of pH, the probes could also image Zn2+ in live cells with remarkable fluorescence variation and provide a new method to visualize monitoring in live cells. (C) 2020 Elsevier Ltd. All rights reserved.