title: Amplified detection of DNA hybridization using post-labelling with a biotin-modified intercalator.
abstract: A 32-electrode microelectrode array modified with a self-assembled monolayer of a thiolated DNA capture strand and 11-mercapto-l1-undecanol was used for the detection of multi-resistant Staphylococcus aureus (MRSA) upon hybridization of the complementary target DNA. In the proposed assay strategy the obtained double-stranded DNA (dsDNA) is at first non-covalently labeled by intercalation of a proflavine derivative which is functionalized via a flexible spacer with biotin moieties. Subsequent to this epost-labelling a avidin/alkaline phosphatase conjugate is bound to the biotin moieties thus introducing a reporter group at sites bearing dsDNA. Hybridization and hence the presence of MRSA DNA is detected via oxidation ofp-aminophenol enzymatically generated from p-aminophenylphosphate. The assay strategy was carefully evaluated using ferrocene-modified target strands. An increase in sensitivity of the proposed label-free DNA assays based on a careful design of the sensing interface and the implemented enzymatic amplification was achieved.
authors.affiliation: Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, Universiätsstr. 150, D-44780 Bochum, Germany.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Gebala
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hartwich
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuhmann
mesh_terms: D001710:Biotin / Q000737:chemistry*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D017403:In Situ Hybridization; D007364:Intercalating Agents / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification; D008839:Microelectrodes; D009693:Nucleic Acid Hybridization / Q000379:methods*; D011199:Potentiometry / Q000379:methods; D013203:Staphylococcal Infections / Q000175:diagnosis*
chemical_list: D004269:DNA, Bacterial; D007364:Intercalating Agents; D001710:Biotin