Development of near-infrared fluorescent probes with AIE properties and their application in the detection and imaging of CN− in environmental water samples and multiple species (zebrafish/cells/plants)

Cyanide ions (CN⁻) are highly toxic pollutants that are widely present in industrial wastewater and the environment, posing a serious threat to ecosystems and human health. The development of highly sensitive and selective CN⁻ detection technologies is an urgent need in environmental monitoring and biomedical fields. In this study, we designed and synthesized a near-infrared fluorescent probe, OTB, based on the aggregation-induced emission (AIE) mechanism. It features a methoxy-modified triphenylamine as the fluorescent moiety and incorporates a benzothiazole structure, achieving an ultra-large Stokes shift of 174 nm and near-infrared emission at 640 nm. The OTB probe achieves fluorescence quenching by CN⁻ mediated affinity addition that disrupts the conjugated structure, with a detection limit as low as 0.451 μM for CN⁻. It also exhibits excellent interference resistance and broad pH stability. This probe has been successfully applied for the quantitative analysis of CN⁻ in various environmental water samples such as tap water and lake water (recovery rate 94 %–110 %) and has achieved fluorescence imaging of CN⁻ in multi-species biological samples including 4T1 cells, zebrafish, and Arabidopsis. This study provides a new technical approach for the efficient detection of cyanide, promoting the cross-application of hazardous substance detection in environmental and biomedical fields. This study proposes a new and efficient method for detecting CN⁻, promoting the application of hazardous substance detection technology in fields such as the environment and biomedicine.