Coral-like silver citrate as robust laccase mimetics in a novel colorimetric aptasensor for sensitive and highly selective detection of histamine in food

The colorimetric methods for histamine detection still face some challenges in accuracy and stability. Herein, a novel colorimetric aptasensor for sensitive and highly selective detection of histamine was developed based on the enhancement of silver citrate (AgCit) laccase-mimic activity. It has been confirmed that H2 aptamer enhances the affinity of AgCit to the chromogenic substrate, and promotes the generation of semiquinone radical in the laccase-mimic catalytical system. The color change of the sensing solution can be distinguished by the naked eye, and easily converted to the corresponding RGB value by a smartphone for the quantitative and rapid detection of histamine. The aptasensor has a limit of detection (LOD) as low as 27 μg·L-1, and maintains high selectivity for histamine in the presence of other competitive substances. It is strongly believed that the design of a colorimetric aptasensor can provide a simple and versatile platform for histamine detection in food.