Aptamer-based fluorescence-quenching lateral flow strip for rapid detection of mercury (II) ion in water samples

Divalent mercury ion (Hg²⁺) is one of the most common and stable forms of mercury pollution. In this study, a skillfully designed lateral flow strip (LFS) was developed for sensitive detection of Hg²⁺ in river water samples. Aptamer, a specific oligonucleotide probe, was used to selectively identify and target Hg²⁺ instead of antibody in traditional immunechromatographic strips; and the fluorescence-quenching system was used to generate positive and low background florescence signals in the competitive-likely LFS. The linear detection range of the LFS for Hg²⁺ was 0.13 ng mL^-1 to 4 ng mL^-1 and the limit of detection (LOD) was 0.13 ng mL^-1. This test provided results in 15 min and demonstrated high specificity. For detection of Hg²⁺ in river water, the results were consistent with inductively coupled plasma-mass spectrometry measurements. The aptamer-based fluorescence-quenching LFS was shown to provide a reliable, accurate method for rapid detection of mercury contamination. Graphical Abstract The principle of the aptamer-based fluorescence-quenching LFS.