Screening and identification of an aptamer as novel recognition molecule in the test strip and its application for visual detection of ethyl carbamate in liquor

There is still a great challenge of on-site and rapid detection for ethyl carbamate (EC) in liquor. Herein, the aptamer (EC1) against EC was firstly screened by Capture-SELEX strategy, and its affinity and binding sites for EC were further investigated by fluorescence assay and molecular docking. Under the premise of retaining the structural features, the obtained aptamer was further truncated into a short sequence (named EC1-34), which has the dissociation constant of 17.97 ± 0.98 nM for EC. Subsequently, a visible, rapid, and cost-effective test strip was firstly designed for EC detection in liquor, in which the cationic polymer was used to efficiently capture the recognition probe conjugated with EC1-34 aptamer and gold nanoparticles (AuNPs). The minimum detection limit of the test strip is calculated as 2.14 μg⋅L-1. The rapid test strip can be widely used for EC detection in liquor due to the advantages of high stability, convenience and selectivity.