A novel fluorescent chemosensor based on coumarin and quinolinyl-benzothiazole for sequential recognition of Cu2+ and PPi and its applicability in live cell imaging.

In this study, a highly selective fluorescent sensor (E)-2-((2-(benzo[ d ]thiazol-2-yl)quinolin-8-yl)oxy)- N ′ -((7-(diethylamino)-2-oxo-2 H -chromen-3-yl)methylene)acetohydrazide (TQC) was synthesized from 2-methylquinolin-8-ol and 4-(diethylamino)-2-hydroxybenzaldehyde and its structure was characterized by 1H NMR, 13C NMR, ESI-HR-MS and density functional theory (DFT) calculation. Sensor TQC showed an obvious "on-off-on" fluorescence response to Cu2+ and PPi in a DMSO/HEPES (3:2 v/v, pH = 7.4) buffer system. The detection limits of sensor TQC were 0.06 μM to Cu2+ and 0.01 μM to PPi. In addition, sensor TQC showed a 1:1 binding stoichiometry to Cu2+ and TQC- Cu2+ complex showed a 2:1 binding stoichiometry to PPi. The optimum pH range of sensor TQC and TQC- Cu2+ was 3–8. Further studies demonstrated that sensor TQC could be made into test paper strips for the qualitative of Cu2+ and PPi and showed sequentially "on-off-on" fluorescent bio-imaging of Cu2+ and PPi in HeLa cells. Unlabelled Image • The sensor TQC could be used to sequential detect Cu2+ and PPi. • The detection limits of sensor TQC were 0.06 μM to Cu2+ and 0.01 μM to PPi. • Test paper strips for the qualitative detection. • Live cell imaging in HeLa cells. [ABSTRACT FROM AUTHOR]