Oligonucleotide-based label-free Hg2+ assay with a monomer-excimer fluorescence switch

A novel fluorescent Hg2+ sensor was developed based on the T-Hg2+-T structure and a thioflavine T monomer-excimer fluorescent switch. Under optimum conditions, the selectivity is remarkably high, and Hg2+ can be quantified over the dynamic range of 0.1 to 1.2 mu M, with a limit of detection (LOD) of similar to 20 nM and a linear correlation coefficient of 0.995.