A coumarinylaldoxime as a specific sensor for Cu²⁺ and its biological application

In this Letter we present a new probe, (E)-7-(diethylamino)-2-oxo-2H- chromene-3-carbaldehyde oxime (JB), which can detect Cu²⁺ ions in HEPES buffer under physiological conditions. Benesi-Hildebrand and Job plots demonstrate that the stoichiometry of the Cu²⁺ complex formed is 2:1. Possible interference with other analytes was examined, and the decrease of the fluorescence of JB at 510 nm when it reacts with Cu²⁺ was shown to be highly selective. This probe accumulates in the plasmalemma of human neuroblastoma SH-SY5Y cells. Molecular dynamics (MD) simulations revealed that JB interacts with the lipid bilayer at the level of the glycerol moieties.