Phenoxazine‐based Near‐infrared Fluorescent Probes for the Specific Detection of Copper (II) Ions in Living Cells

Abstract

It is well known that copper ions play a critical role in various physiological processes. However, a variety of human diseases are tightly correlated with copper overload. Although there are numerous fluorescent probes capable of detecting copper ions, most of them are "turn-off" probes owing to copper (II) ions fluorescence quenching effect, resulting in poor sensitivity. Herein, a novel "turn-on" near-infrared (NIR) fluorescent probe PZ-N based on phenoxazine was designed and synthesized for the selective detection of copper (II) ions (Cu²⁺ ). Upon the addition of Cu²⁺ , the probe could quickly react with Cu²⁺ and emit strong fluorescence, along with colour change from colourless to obvious blue. Moreover, the probe PZ-N showed good water solubility, high selectivity, and excellent sensitivity with low limit of detection (1.93 nM) towards copper (II) ions. More importantly, PZ-N was capable of effectively detecting Cu²⁺ in living cells.