Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
2009-6-24
pubmed:abstractText
An approach for visual and fluorescent sensing of Hg2+ in aqueous solution is presented. This method is based on the Hg(2+)-induced conformational change of a thymine (T)-rich single-stranded DNA (ssDNA) and the difference in electrostatic affinity between ssDNA and double-stranded (dsDNA) with gold nanoparticles. The dye-tagged ssDNA containing T-T mismatched sequences was chosen as Hg2+ acceptor. At high ionic strength, introduction of the ssDNA to a colloidal solution of the aggregates of gold nanoparticles results in color change, from blue-gray to red of the solution, and the fluorescence quenching of the dye. Binding of Hg2+ with the ssDNA forms the double-stranded structure. This formation of dsDNA reduces the capability to stabilize bare nanoparticles against salt-induced aggregation, remaining a blue-gray in the color of the solution, but fluorescence signal enhancement compared with that without Hg2+. With the optimum conditions described, the system exhibits a dynamic response range for Hg2+ from 9.6 x 10(-8) to 6.4 x 10(-6) M with a detection limit of 4.0 x 10(-8) M. Both the color and fluorescence changes of the system are extremely specific for Hg2+ even in the presence of high concentrations of other heavy and transition metal ions, which meet the selective requirements for biomedical and environmental application. The combined data from transmission electron microscopy, fluorescence anisotropy measurements, and dialysis experiments indicate that both the color and the fluorescence emission changes of the DNA-functioned gold nanoparticles generated by Hg2+ are the results of the metal-induced formation of dsDNA and subsequent formation of nanoparticle aggregates.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0003-2700
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
80
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9021-8
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Gold nanoparticle-based colorimetric and "turn-on" fluorescent probe for mercury(II) ions in aqueous solution.
pubmed:affiliation
Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Evaluation Studies