Abstract: Based on the aggregation-induced emission (AIE) characteristics of 9,10-distyryl sulfonium quaternary ammonium salt (DSAI), a method for the detection Ag+ was developed by a combination of aptamer recognition and fluorescence resonance energy transfer. When Ag+ was added, the target and the aptamer specifically bound to each other, forming a U-shaped structure which could cause conformational changes in the aptamer. At the same time, the adsorbed aptamer was desorbed from the black phosphorus nanosheets (BPNS) and then combined with DSAI by electrostatic adsorption and hydrophobic interaction, enhancing the fluorescence intensity of the solution system. In order to develop the Ag+ detection method, a fluorescent aptamer sensor based on AIE was constructed, which showed a good linear relationship within the concentration range of 0.01–100 ng/mL, and the limit of detection (LOD) was 0.002 ng/mL. Thanks to its advantages such as simplicity, easy operation, low cost, good sensitivity and high selectivity, this aptasensor can also apply to other targets.

Key words: food safety, aggregation-induced emission, fluorescent probe, detection limit, fluorescent aptasensor