Construction of a New Probe Based on Copper Chaperone Protein for Detecting Cu²⁺ in Cells

Biomacromolecular probes have been extensively employed in the detection of metal ions for their prominent biocompatibility, water solubility, high selectivity, and easy modification of fluorescent groups. In this study, a fluorescent probe FP was constructed. The probe FP exhibited high specificity recognition for Cu²⁺. With the combination of Cu²⁺, the probe was subjected to fluorescence quenching. The research suggested that the probe FP carried out the highly sensitive detection of Cu²⁺ with detection limits of 1.7 nM. The fluorescence quenching of fluorescamine was induced by Cu²⁺ perhaps due to the PET (photoinduced electron transfer) mechanism. The FP-Cu²⁺ complex shows weak fluorescence, which is likely due to the PET quenching effect from Cu²⁺ to fluorescamine fluorophore. Moreover, the probe FP can be employed for imaging Cu²⁺ in living cells. The new fluorescent probe developed in this study shows the advantages of good biocompatibility and low cytotoxicity. It can be adopted for the targeted detection of Cu²⁺ in cells, and it has promising applications in the mechanism research and diagnosis of Cu²⁺-associated diseases.