title: Detection of lead(II) ions with a DNAzyme and isothermal strand displacement signal amplification.
abstract: A DNAzyme based method for the sensitive and selective quantification of lead(II) ions has been developed. A DNAzyme that requires Pb(2+) for activation was selected. An RNA containing DNA substrate was cleaved by the DNAzyme in the presence of Pb(2+). The 2',3'-cyclic phosphate of the cleaved 5'-part of the substrate was efficiently removed by Exonuclease III. The remaining part of the single stranded DNA (9 or 13 base long) was subsequently used as the primer for the strand displacement amplification reaction (SDAR). The method is highly sensitive, 200 pM lead(II) could be easily detected. A number of interference ions were tested, and the sensor showed good selectivity. Underground water samples were also tested, which demonstrated the feasibility of the current approach for real sample applications. It is feasible that our method could be used for DNAzyme or aptazyme based new sensing method developments for the quantification of other target analytes with high sensitivity and selectivity.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Yang
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Fangyuan
authors.initials: F
authors.lastname: Wang
authors.forename: Cong
authors.initials: C
authors.lastname: Yu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D021881:DNA, Catalytic / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D005090:Exodeoxyribonucleases / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007477:Ions / Q000737:chemistry / Q000302:isolation & purification*; D007854:Lead / Q000737:chemistry / Q000302:isolation & purification*; D057230:Limit of Detection; D012313:RNA / Q000737:chemistry
chemical_list: D021881:DNA, Catalytic; D004277:DNA, Single-Stranded; D007477:Ions; D007854:Lead; D012313:RNA; D006046:Gold; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III
keywords: DNAzyme; Exonuclease III; Fluorescence; Lead; Strand displacement amplification