A Simple and Selective Colorimetric Aptasensor for Detection of Toxins Microcystin-LR in Fish Tissue Using a Truncated Aptamer

In the present study, a sensitive and simple approach for colorimetric detecting microcystin-LR (MC-LR) in fish tissue was developed based on gold nanoparticles (AuNPs) and a truncated aptamer Apt-910–2, which was obtained by mutation and rational truncation from the previously selected 60-mer one. The 23-mer Apt-910–2 presented improved binding affinity to MC-LR and higher specificity. Under the optimum experimental conditions, the Apt-910–2 colorimetric aptasensor worked well in 10 to 150 ng/mL MC-LR concentration ranges, and the limit of detection (LOD) was 0.38 ng/mL. This Apt-910–2 colorimetric aptasensor was also applied to spiked fish tissue samples and gave recovery rates ranged from 75.18 to 87.72%, with the visual LOD 10 μg/kg in fish tissue judged by the naked eye. Thus, this study provides a rapid, reliable, and convenient approach for visual detection of MC-LR, which is of great significance for food safety control by assessing potential health risks related to seafood consumption.