An ESIPT active coumarin-diphenyl azine-based AIEgen: Nanomolar Cu2+ ion sensing, Latent Fingerprinting, live-cell imaging, and real sample analysis

Designing economical and sensitive chemosensors for detecting important metal ions, like Cu2+ ions, is essential and remains a hot topic worldwide. In this investigation, we extended our investigation to design a specific diphenyl-azine-based skeletal system for the selective and sensitive detection of Cu2+ ions. We reported a coumarin-diphenyl-azine-based AIEgen (C-1) using an improvised methodology with a large Stoke's shift (∼245 nm) for precisely sensing copper ions in solid, solution, and biological cells. The AIE-ESIPT properties of C-1 were validated using various sophisticated techniques. C-1 was found to be a promising selective and sensitive sensor of Cu2+ ions (nanomolar LOD value ∼10.38 nM) via colorimetric and TURN-OFF fluorometric ways. The practical applicability of C-1 was analyzed via real-time estimation of copper ions in water samples (obtained from three varied locations) and in biological samples (urine and serum). The satisfactory recovery with a low RSD value indicates the potential of C-1 in detecting copper ions in actual samples. Estimating copper ions in urine and blood samples demonstrates the usefulness of C-1 in diagnosing disorders like Wilson's disease, which is caused by high concentrations of copper ions in the body. Additionally, we have detected Cu2+ ions in live cells (HeLa cells) and carried out Latent Fingerprinting (Level 1 and Level 2) to validate its versatility in physiological and forensic applications. Overall, the proposed C-1 AIEgen is an ultrasensitive Cu2+ ions sensor with innumerable applications in the physical world.