title: A selective amperometric sensing platform for lead based on target-induced strand release.
abstract: A novel strategy for selective and sensitive amperometric detection of lead ion (Pb(2+)) was proposed based on target-induced strand release. The underlying gold electrode was pre-modified with dendritic gold nanoparticles by direct electrodeposition to afford increased electrode surface area for immobilization of thiol group-containing capture DNA molecules. The hybridization of the capture DNA molecules with Pb(2+)-specific aptamer molecules to form a DNA duplex, into which methylene blue was intercalated, induced measurable electrochemical signal. Upon addition of Pb(2+), it could specifically bind to its aptamer to form Pb(2+)-stablized G-quadruplex and induce the aptamer strand to release from the electrode surface into solution, accompanied by the release of intercalated MB responsible for significant signal reduction. The fabricated biosensor showed a linear response to the logarithm of Pb(2+) concentration over the range of 1.0 × 10(-10) M to 1.0 × 10(-7) M with a detection limit of 7.5 × 10(-11) M. In addition, this strategy afforded an exquisite selectivity for Pb(2+) against other metal ions. The excellent sensitivity and selectivity show good potential for Pb(2+) detection in real environmental samples.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan 250014, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Limin
authors.initials: L
authors.lastname: Yang
authors.forename: Mingqin
authors.initials: M
authors.lastname: Chen
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Tang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques; D021881:DNA, Catalytic / Q000737:chemistry; D055664:Electrochemical Techniques; D004787:Environmental Pollution / Q000032:analysis; D054856:G-Quadruplexes; D006046:Gold / Q000737:chemistry; D007477:Ions / Q000032:analysis* / Q000737:chemistry; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D021881:DNA, Catalytic; D007477:Ions; D009841:Oligonucleotides; C116759:T 30695; D007854:Lead; D006046:Gold