Detection of chloramphenicol in aquatic products using a colorimetric aptasensor based on catalytic hairpin assembly and G-quadruplex

Abstract

The development of a novel approach for the quantification of chloramphenicol (CAP) residues in aquatic products is of paramount importance for the assurance of food safety. In this study, a colorimetric aptasensor based on the Catalytic Hairpin Assembly (CHA) and G-quadruplex was established for the rapid detection of chloramphenicol (CAP) in aquatic products. In the presence of CAP, the specific binding effect results in the dissociation of CAP-sensitive aptamer-TDNA (A-T), thereby releasing tDNA. This in turn triggers a CHA reaction, which achieves enzyme-free signal amplification. This results in the release of G-quadruplex, which causes substrate Tetramethylbenzidine (TMB) oxidation and a change in colour and absorbance values. Consequently, a rapid, sensitive and economical visual qualitative and quantitative detection of CAP is achieved. The visual limit of qualitative detection was 80 ng/mL, the quantitative limit of detection was 90 pg/mL, and the linear range was 0.0001–100 μg/mL. The sensor exhibits high specificity and good repeatability (RSD: 4.14 %), with a recovery rate of 83 % to 103.5 %. These characteristics indicate that the colorimetric aptasensor has significant potential for application in food safety detection and provides a viable new platform for the detection of CAP in aquatic products.