title: Colorimetric assay for mercury (II) based on mercury-specific deoxyribonucleic acid-functionalized gold nanoparticles.
abstract: A colorimetric nanoprobe-mercury-specific DNA-functionalized gold nanoparticles (Au-MSD) was developed for sensing Hg(2+). The new mercury-sensing concept relies on measuring changes in the inhibition of "non-crosslinking" aggregation of Au-MSD-induced by the folding of mercury-specific DNA strand through the thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination. In the absence of Hg(2+), a high concentration of MgCl(2) (50 mM) results in a rapid aggregation of Au-MSD because of the removal of charge repulsion. When Hg(2+) is present, the particles remain stable due to the folding of MSD functionalized on the particle surface. The assay enables the colorimetric detection of Hg(2+) in the concentration range of 0.1-10 μM Hg(2+) ions with a detection limit of 60 nM, and allows for the selective discrimination of Hg(2+) ions from the other competitive metal ions. Toward the goal for practical applications, the sensor was further evaluated by monitoring Hg(2+) in fish tissue samples.
authors.affiliation: Department of Chemistry, East China Normal University, Shanghai, China.
authors.forename: Jikui
authors.initials: J
authors.lastname: Wu
authors.forename: Lanying
authors.initials: L
authors.lastname: Li
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.forename: Pingang
authors.initials: P
authors.lastname: He
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Fang
authors.forename: Guifang
authors.initials: G
authors.lastname: Cheng
mesh_terms: D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D015636:Magnesium Chloride / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry
chemical_list: D015636:Magnesium Chloride; D006046:Gold; D004247:DNA; D008628:Mercury; D013941:Thymine