Fluorescence analysis for Mercuric Ion based on DNA-Functionalized Gold Nanoparticles

• 1、School of Chemistry and Engineering, Henan Normal University, Xinxiang 453007

Abstract：This paper describes a fluorescence spectrometric approach for detecting Hg2+ in aqueous solution using thiol-DNA-functionalized gold nanoparticles. This method is based on Hg2+-induced conformational change of ssDNA and an enhanced fluorescence resonance energy transfer (FRET) process between the donor (fluorescein) and acceptor (gold nanoparticles) at the termini of ssDNA. In the presence of Hg2+, a formation of a hairpin structure for ssDNA originates from T-Hg2+-T interaction, resulting in notable fluorescence quenching in comparison to the random coil. In order to improve the stability and sensitivity of the sensor, we adopt short "helper" oligonucleotides to increase the density of DNA from the surface of the Au NPs. The assay enables the detection limit of this method for Hg2+ is 8 nM, and is extremely speci?c for Hg2+ even in the presence of high concentrations of other competitive metal ions. Toward the goal for practical applications, this simple sensor was applied to monitor Hg2+ in tap water samples and showed low matrix interference and high sensitivity.

Keywords： Hg2+ detection fluorescence gold nanoparticles oligonucleotides