Coumarin-Derived Cu²⁺-Selective Fluorescence Sensor: Synthesis, Mechanisms, and Applications in Living Cells

TLDR

The authors designed a coumarin‑based fluorogenic probe that selectively binds Cu²⁺ over other metal ions, enabling its use as a biological chemosensor. The probe’s fluorescence “on‑off” response was characterized by femtosecond time‑resolved fluorescence and ab initio calculations, and it functions across a pH range of 4–10 in aqueous media. Experiments demonstrated that the probe can image intracellular Cu²⁺ in cultured cells, making it a useful tool for studying copper’s biological roles.

Abstract

A novel coumarin-based fluorogenic probe bearing the 2-picolyl unit (1) was developed as a fluorescent chemosensor with high selectivity and suitable affinity in biological systems toward Cu2+ over other cations tested. The fluorescence on−off mechanism was studied by femtosecond time-resolved fluorescence (TRF) upconversion technique and ab initio calculations. The receptor can be applied to the monitoring of Cu2+ ion in aqueous solution with a pH span 4−10. To confirm the suitability of 1 for biological applications, we also employed it for the fluorescence detection of the changes of intracellular Cu2+ in cultured cells. The results indicate that 1 should be useful for the fluorescence microscopic imaging and the study on the biological functions of Cu2+.