“Molecular beacon”-hosted thioflavin T: Applications for label-free fluorescent detection of iodide and logic operations

In this work, we presented a simple, label-free and rapid-responsive fluorescence assay for iodide (I − ) detection based on “molecular beacon (MB)”-hosted thioflavin T (ThT), achieving a limit of detection as low as 158   nM. The proposed method exhibited very good selectivity to I − ions over other anions interference due to the strong binding force between I − ions with Hg 2+ . Upon the addition of I − ions, it would capture Hg 2+ from a T–Hg 2+ –T complex belonging to the MB-like DNA hairpin structure, which eventually quenched the initial fluorescence as output. In addition, it was successfully applied for operation of an integrated DNA logic gate system and to the determination of I − in real samples such as human urine.