title: Selective and sensitive mercuric (ii) ion detection based on quantum dots and nicking endonuclease assisted signal amplification.
abstract: This work reports a novel signal amplification method for Hg(2+) detection based on quantum dots (QDs) and nicking endonuclease (NEase). In this assay, streptavidin-coated QDs were conjugated to biotinylated hairpin-shaped probe A which was modified with a quencher BHQ-2. The fluorescence of the QDs was quenched by BHQ-2 through FRET quenching. In the presence of Hg(2+), probe B hybridized with the loop of probe A due to specific binding between thymine-thymine mismatches and Hg(2+), thus probe A was opened. Then NEase recognized specific nucleotide sequences and cleaved probe A. After the dissociation of probe A fragments, the distance between QDs and BHQ-2 increased, which led to increase of QDs fluorescence. The released Hg(2+) and probe B could hybridize with another probe A to start a new cycle, therefore a remarkable signal amplification was achieved. Under optimal conditions, the detection limit of this assay was 8.0×10(-10)mol L(-1).
authors.affiliation: School of Pharmacy, Shandong University, 250012 Jinan, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Chen
authors.forename: Zhun
authors.initials: Z
authors.lastname: Hou
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004720:Endonucleases / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D008163:Luminescent Measurements / Q000295:instrumentation*; D008628:Mercury / Q000032:analysis / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry*; D045663:Quantum Dots
chemical_list: D007477:Ions; D009841:Oligonucleotides; D004720:Endonucleases; D008628:Mercury