Highly selective and portable fluorescent detection of uranyl in groundwater via AIEgen-labeled protein cleavage

To achieve highly selective and portable detection of uranyl (UO₂²⁺) in potentially polluted groundwater, a fluorescent detection method based on UO₂²⁺-triggered protein cleavage was established. An aggregation-induced emission luminogen (AIEgen), 4-aldehyde-4′,4″-bis(4-pyridyl)triphenylamine, (CHO-BIPY-TPA, abbreviated as CBPT), was synthesized and labeled onto bovine serum albumin (BSA). The fluorescence of CBPT-BSA was quenched by UO₂²⁺-triggered covalent bond cleavage and protein fragment release. A linear response was observed in the range of 0.1–12 nM with a LOD of 0.01 nM, significantly outperforming the World Health Organization's drinking water limit (60 nM). Selectivity tests confirmed negligible interference from coexisting metal ions as only UO₂²⁺ could triggered protein cleavage. In additon, a portable device was designed for on-site detection of UO₂²⁺ in underground water, which exhibited a linear response in the range of 0.1–15 nM with a LOD of 0.06 nM. The spiked recovery rate reached 85–96 % in environmental water samples, with a relative standard deviation (RSD) below 8 %. The study provided a selective and sensitive screening platform for on-site monitoring UO₂²⁺ in environmental samples.