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.