A BODIPY-based fluorescent chemosensor for Cu2+ and biological thiols, and its application as a Cu2+ probe in live cell imaging

A new fluorescent boron dipyrromethene (Bodipy) derivative 1 containing a di(2-picolyl)amine group as a binding site for Cu2+ was synthesized and characterized. Compound 1 behaves as an “on–off” fluorescent sensor for highly selective and sensitive detection of Cu2+ ions. The selective interaction between compound 1 and Cu2+ leads to formation of a 1·Cu2+ complex, associated with quenching of the fluorescence of 1. An investigation into the detection of biothiols shows that the 1·Cu2+ complex has better recognition for glutathione than cysteine and homocysteine in CH3OH–HEPES (1:1, v/v) buffer solution at pH 7.4 (HEPES = 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid). In addition, fluorescence images obtained via confocal microscopy reveal that compound 1 exhibits excellent selectivity and high sensitivity for Cu2+ under physiological conditions and in living cells.