title: Target-induced electronic switch for ultrasensitive detection of Pb2+ based on three dimensionally ordered macroporous Au-Pd bimetallic electrode.
abstract: A novel strategy for selective and sensitive amperometric detections of Pb(2+) was proposed based on the three dimensional ordered macroporous (3DOM) Au-Pd bimetallic electrode and target-induced methylene blue-single walled carbon nanotubes (MB-SWCNTs) as signal reporter. A DNA biosensor was fabricated by immobilizing capture probe DNA on the 3DOM Au-Pd bimetallic electrode, which further hybridized with the reporter DNA loaded on the MB-SWCNTs adduct upon the exposure of Pb(2+), inducing measurable electrochemical signal. Due to the dramatic signal amplification by the enhanced immobilization of DNA on the surface of 3DOM Au-Pd bimetallic electrode and MB-SWCNTs, coupling the low background signal produced by blank solution, ultra-low level (1 × 10(-19)M) of Pb(2+) could be detected. Under the optimal conditions, the electrochemical signal of the MB increased with the increasing Pb(2+) concentration, exhibiting a linear response in the range of 1 × 10(-17)-1 × 10(-4)M. Furthermore, with the application of Pb(2+) dependent DNAzyme, the proposed sensing system demonstrated high selectivity. This work represented a promising potential for on-site testing Pb(2+) in real drinking water and serum sample analysis.
authors.affiliation: College of Sciences, Nanjing University of Technology, Nanjing 211816, PR China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China. Electronic address: chenxj_njut@126.com.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Chen
authors.forename: Rong
authors.initials: R
authors.lastname: Tian
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Cheng
authors.initials: C
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000737:chemistry; D021881:DNA, Catalytic / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D007854:Lead / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D021881:DNA, Catalytic; D014874:Water Pollutants, Chemical; D007854:Lead; D006046:Gold; D004247:DNA
keywords: Au–Pd bimetallic electrode; DNAzyme biosensor; Lead detection; Methylene blue modified carbon nanotubes; Three dimensional ordered macroporous materials