Amplified biosensing using the horseradish peroxidase-mimicking DNAzyme as an electrocatalyst

Gilad Pelossof, Ran Tel-Vered, Johann Elbaz, Itamar Willner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

223 Scopus citations


The hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme is assembled on Au electrodes. It reveals bioelectrocatalytic properties and electrocatalyzes the reduction of H2O2. 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 H2O2, provide a quantitative measure for the detection of the target analytes. The DNA target was analyzed with a detection limit of 1 × 10-12 M, while the detection limit for analyzing AMP was 1 × 10-6 M. Methods to regenerate the sensing surfaces are presented.

Original languageEnglish
Pages (from-to)4396-4402
Number of pages7
JournalAnalytical Chemistry
Issue number11
StatePublished - 1 Jun 2010
Externally publishedYes


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