Design an aptamer-recognized visual nanozyme sheet for rapid detection of ethyl carbamate in liquor

The convenient detection of ethyl carbamate (EC) still faces some challenges due to certain interfering substances in liquor. Herein, the peroxidase-mimic activity of V6O13 nanobelts was inhibited by EC1-34 aptamer, and a novel rapid method for EC detection was established using EC1-34 aptamer as a specific recognition molecule. The composite probe consisting of V6O13 nanobelts and EC1-34 aptamer was immobilized on the paper to construct a colorimetric nanozyme sheet. The presence of EC1-34 aptamer would effectively inhibit the peroxidase-mimic activity of V6O13 nanobelts, making the colorimetric nanozyme sheet exhibit light blue or even colorless. Once the EC was added to nanozyme sheet, the EC1-34 preferentially bound to EC molecules, restoring the peroxidase-like activity of V6O13 nanobelts. The degree of the blue-gray change of the constructed colorimetric nanozyme sheets was positively correlated with the EC concentration. Moreover, a smartphone was used to assist in obtaining the image data and then drawing a standard curve. The visual limit of detection of the rapid colorimetric nanozyme sheets was 20 μg·L-1, and the limit of detection (LOD) was calculated as 14.17 μg·L-1. The novel rapid detection nanozyme sheets constructed in this study can be generally applied in detecting EC in liquor.