Characterization of a highly Cu2+-selective fluorescent probe derived from rhodamine B

A rhodamine B derivative was synthesized and characterized as a highly selective and sensitive probe for Cu2+ in ethanol–water solution (2:3, v:v, pH7.4, 50 mM HEPES). A prominent fluorescence enhancement at 575 nm was observed in the presence of Cu2+, accompanied by the change in the absorption spectrum. Under the optimal conditions, a good linear range of 0.5–1.5 μM with a detection limit of 1.6 × 10−7 M were obtained. Furthermore, confocal laser scanning microscopy experiments have proven that this probe is cell-permeable and can respond to changes in intracellular Cu2+ in living cells.

Graphical abstractA rhodamine B derivative was synthesized and characterized as Cu2+-selective probe in ethanol-water solution (2:3, v:v, pH7.4, 50 mM HEPES) with remarkable fluorescence enhancement and clear color change. Confocal laser scanning microscopy experiments have proven that this probe is cell-permeable and can respond to changes in intracellular Cu2+ in living cells.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► It could specifically recognize Cu2+ from fluorescence “off” to fluorescence “on”. ► L has good selectivity and sensitivity to Cu2+. ► The new chemsensor L was successfully used for the detection of Cu2+ in the living cells.