T-Hg2+-T-based satellite structured surface enhanced Raman scattering sensor for Hg2+ detection

Mercury ion (Hg2+) exposure is a threat to human health. We report a plasmonic core-satellite Fe3O4@SiO2-Au (FA) hetero nanostructure for Hg2+ detection using surface enhanced Raman scattering based on the T-Hg2+-T strategy. The FA nanostructure was functionalized by a DNA aptamer, which was designed with Cy5 at the 5 end, and used as a Raman reporter to specifically bind to Hg2+ ions. In the presence of Hg2+, DNA formed a hairpin structure, bringing Cy5 close to the FA hotspots region, thus generating an enhanced Raman signal. The T-Hg2+-T complex formed the basis for the determination of trace Hg2+ with a detection limit lower than 5x10(-9)M, and the influence of other metal ions was found to be negligible. With high selectivity, sensitivity, and recyclability, this FA-DNA surface enhanced Raman scattering platform is a promising tool for field monitoring of Hg2+ ions.