title: Label-free emission assay of mercuric ions using DNA duplexes of poly(dT).
abstract: In this study, an assay to quantify the presence of mercuric ions and methyl mercury by double-stranded DNA containing a poly(dT) sequence was developed using a light switch compound, Ru(phen)(2)(dppz)(2+) (1), which is known to intercalate into double-stranded DNA. Upon treatment with mercuric ions, the metal-to-ligand charge transfer (MLCT) emission derived from the intercalation of 1 was reduced due to the formation of DNA duplexes containing T-Hg(2+)-T base pairs by the dehybridization of poly(dT)-poly(dA) duplexes at room temperature. As the concentration of Hg(2+) was increased, the emission of 1 gradually decreased. This label-free method had a detection limit of 5 nM. Other metal ions, such as K(+), Ag(+), Ca(2+), Mg(2+), Zn(2+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Cd(2+), Cr(3+), Fe(3+), had no significant effect on reducing emission. This emission method can differentiate matched and mismatched poly(dT) sequences based on the dehybridization rate of dsDNA and the rate decreased in the order of T(10)C·A(11)∼ T(10)A·A(11) > T(10)G·A(11) > T(11)·A(11).
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Byul Nim
authors.initials: BN
authors.lastname: Oh
authors.forename: Sangji
authors.initials: S
authors.lastname: Park
authors.forename: Jun
authors.initials: J
authors.lastname: Ren
authors.forename: Yoon Jung
authors.initials: YJ
authors.lastname: Jang
authors.forename: Seog K
authors.initials: SK
authors.lastname: Kim
authors.forename: Jinheung
authors.initials: J
authors.lastname: Kim
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D005470:Fluorometry / Q000379:methods*; D007364:Intercalating Agents / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D011071:Poly T / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D007364:Intercalating Agents; D007477:Ions; D011071:Poly T; D012428:Ruthenium; D004247:DNA; D008628:Mercury