title: Amplified biosensing using the horseradish peroxidase-mimicking DNAzyme as an electrocatalyst.
abstract: The hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme is assembled on Au electrodes. It reveals bioelectrocatalytic properties and electrocatalyzes the reduction of H(2)O(2). The bioelectrocatalytic functions of the hemin/G-quadruplex DNAzyme are used to develop electrochemical sensors that follow the activity of glucose oxidase and biosensors for the detection of DNA or low-molecular-weight substrates (adenosine monophosphate, AMP). Hairpin nucleic structures that include the G-quadruplex sequence in a caged configuration and the nucleic acid sequence complementary to the analyte DNA, or the aptamer sequence for AMP, are immobilized on Au-electrode surfaces. In the presence of the DNA analyte, or AMP, the hairpin structures are opened, and the hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme structures are generated on the electrode surfaces. The bioelectrocatalytic cathodic currents generated by the functionalized electrodes, upon the electrochemical reduction of H(2)O(2), provide a quantitative measure for the detection of the target analytes. The DNA target was analyzed with a detection limit of 1 x 10(-12) M, while the detection limit for analyzing AMP was 1 x 10(-6) M. Methods to regenerate the sensing surfaces are presented.
authors.affiliation: Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Gilad
authors.initials: G
authors.lastname: Pelossof
authors.forename: Ran
authors.initials: R
authors.lastname: Tel-Vered
authors.forename: Johann
authors.initials: J
authors.lastname: Elbaz
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D000249:Adenosine Monophosphate / Q000032:analysis; D052157:Aptamers, Nucleotide / Q000032:analysis; D055162:Biocatalysis; D040761:Biomimetic Materials / Q000378:metabolism*; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis / Q000737:chemistry; D021881:DNA, Catalytic / Q000378:metabolism*; D004563:Electrochemistry; D054856:G-Quadruplexes; D005947:Glucose / Q000032:analysis; D006427:Hemin / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism; D010084:Oxidation-Reduction
chemical_list: D052157:Aptamers, Nucleotide; D021881:DNA, Catalytic; D000249:Adenosine Monophosphate; D006427:Hemin; D004247:DNA; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D005947:Glucose