A quinoline-based ratiometric and reversible fluorescent probe for cadmium imaging in living cells

Abstract

We report a novel ratiometric and reversible fluorescent probe for Cd2+ detection utilizing a 6-(dimethylamino)quinaldine derivative as the fluorophore and a 2-hydrazinopyridine derivative as Cd2+ chelator. This ratiometric fluorescent probe possesses favorable photophysical properties. It shows a large (55 nm) red-shift from 515 nm to 570 nm in the emission spectrum. Moreover, this probe also exhibits an excellent linear relationship of fluorescence intensity ratio (F570/F515) (R2=0.989) vs. Cd2+ concentration in the range of 0-10 μm at physiological pH, which can serve as a "quantitative detecting" probe for Cd2+. Utilizing this sensitive and selective probe, we have successfully detected Cd2+ in living cells.