Gold Nanoparticle-based Dynamic Light Scattering Assay for Detection of Mercury Ion / 分析化学

ABSTRACT

A gold nanoparticle ( GNP)-based dynamic light scattering ( DLS) assay has been developed for detecting mercury ion ( Hg2+) in aqueous solution. The GNPs are able to maintain monodisperse state in relative high ionic strength ( 0. 1 mol/L NaCl ) aqueous solution because Hg2+ aptamer 5’-TTTCTTCTTTCTTCCCCCCTTGTTTGTTGTTT-3’( Probe DNA ) can adsorb on the GNP surface by electrostatic interaction. In the presence of Hg2+, the Probe DNA molecules easily desorb from GNP surface because of T-Hg2+-T formation. The unprotected GNPs form aggregates in 100 mmol/L NaCl solution, resulting in increased significantly the average hydrodynamic diameter of GNPs. Under the conditions of pH 7. 43, 110 nmol/L aptamer, 100 mmol/L NaCl and 30 minutes incubation time of Hg2+with aptamer, the difference of average hydrodynamic diameter (△D ) of GNPs was increased linearly with logarithm of Hg2+concentration over the range from 0. 1 nmol/L to 5 μmol/L, with a detection limit of 0. 1 nmol/L. Moreover, satisfactory results were obtained when the proposed method was applied to detect Hg2+ in real samples.