title: Ultrasensitive Label-Free Resonance Rayleigh Scattering Aptasensor for Hg(2+) Using Hg(2+)-Triggered Exonuclease III-Assisted Target Recycling and Growth of G-Wires for Signal Amplification.
abstract: A novel signal-on and label-free resonance Rayleigh scattering (RRS) aptasensor was constructed for detection of Hg(2+) based on Hg(2+)-triggered Exonuclease III-assisted target recycling and growth of G-quadruplex nanowires (G-wires) for signal amplification. The hairpin DNA (H-DNA) was wisely designed with thymine-rich recognition termini and a G-quadruplex sequence in the loop and employed as a signal probe for specially recognizing trace Hg(2+) by a stable T-Hg(2+)-T structure, which automatically triggered Exonuclease III (Exo-III) digestion to recycle Hg(2+) and liberate the G-quadruplex sequence. The free G-quadruplex sequences were self-assembled into guanine nanowire (G-wire) superstructure in the presence of Mg(2+) and demonstrated by gel electrophoresis. The RRS intensity was dramatically amplified by the resultant G-wires, and the maximum RRS signal at 370 nm was linear with the logarithm of Hg(2+) concentration in the range of 50.0 pM to 500.0 nM (R = 0.9957). Selectivity experiments revealed that the as-prepared RRS sensor was specific for Hg(2+), even coexisting with high concentrations of other metal ions. This optical aptasensor was successfully applied to identify Hg(2+) in laboratory tap water and river water samples. With excellent sensitivity and selectivity, the proposed RRS aptasensor was potentially suitable for not only routine detection of Hg(2+) in environmental monitoring but also various target detection just by changing the recognition sequence of the H-DNA probe.
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.|College of Chemistry and Pharmaceutical Engineering, Sichuan Provincial Academician (Expert) Workstation, Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan, Sichuan University of Science and Engineering , Zigong 643000, People's Republic of China.
authors.forename: Wang
authors.initials: W
authors.lastname: Ren
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.|College of Chemistry and Pharmaceutical Engineering, Sichuan Provincial Academician (Expert) Workstation, Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan, Sichuan University of Science and Engineering , Zigong 643000, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
authors.forename: Hong Guo
authors.initials: HG
authors.lastname: Chen
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
authors.forename: Zhong Feng
authors.initials: ZF
authors.lastname: Gao
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
authors.forename: Nian Bing
authors.initials: NB
authors.lastname: Li
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
authors.forename: Hong Qun
authors.initials: HQ
authors.lastname: Luo
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000737:chemistry / Q000378:metabolism*; D054856:G-Quadruplexes; D008628:Mercury / Q000032:analysis* / Q000378:metabolism*; D049329:Nanostructures / Q000737:chemistry*; D021141:Nucleic Acid Amplification Techniques; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance
chemical_list: D052157:Aptamers, Nucleotide; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D008628:Mercury