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

To achieve highly selective and portable detection of uranyl (UO) in potentially polluted groundwater, a fluorescent detection method based on UO-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 UO-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 UO could triggered protein cleavage. In additon, a portable device was designed for on-site detection of UO 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 UO in environmental samples.