title: An ultrasensitive electrochemical sensing platform for Hg2+ based on a density controllable metal-organic hybrid microarray.
abstract: A novel electrochemical Hg(2+) biosensor was developed on the basis of a metal-organic hybrid microarray, in which the nicking endonuclease (NE) assisted target-triggered strand release strategy was realized via the DNA cyclic amplification technique. The metal-organic hybrid microarray was fabricated using the SAM of 1, 4-benzenendithiol as soft template, and the density of the microarray could be adjusted by controlling the surface coverage of 1,4-benzenendithiol molecules. In the presence of Hg(2+), capture DNA (cDNA) with an indicator at one end could hybridize with the reporter DNA (rDNA) through the stable T-Hg(2+)-T linkage, forming the nicking recognition site. After the nicking reaction, the electrochemical indicator dissociated from the electrode surface. The released rDNA and Hg(2+) could be reused in the sensing system and initiate the next cycle, and more electroactive indicator dissociated from the electrode surface, resulting in a significant signal decrease. The constructed DNA biosensor could detect Hg(2+) in a wide linear range from 15 pM to 500 nM, with an ultrasensitive detection limit of 5 pM (S/N=3). Furthermore, the biosensor exhibited excellent stability, good reproducibility and high selectivity towards other divalent ions. The proposed sensing system also showed a promising potential for the application in real aquatic product sample analysis.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China. Electronic address: wqjin@njut.edu.cn.
authors.forename: Wanqin
authors.initials: W
authors.lastname: Jin
authors.affiliation: College of Sciences, Nanjing University of Technology, Nanjing 210009, PR China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation; D002413:Cations, Divalent / Q000032:analysis; D004247:DNA / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D008670:Metals / Q000737:chemistry; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation*; D015203:Reproducibility of Results
chemical_list: D002413:Cations, Divalent; D008670:Metals; D004247:DNA; D008628:Mercury
keywords: DNA cyclic amplification; Electrochemical DNA biosensor; Hg(2+) detection; Metal-organic hybrid microarray; Nicking endonuclease