Controlled orientation of DNA in a binary SAM as a key for the successful determination of DNA hybridization by means of electrochemical impedance spectroscopy.
Determination of DNA hybridization at electrode surfaces modified with thiol-tethered single-stranded DNA (ssDNA) capture probes and co-assembled with short-chain thiol derivatives using electrochemical impedance spectroscopy requires a careful design of the electrode/electrolyte interface as well as an in-depth understanding of the processes at the interface during DNA hybridization. The influence of the electrode potential, the ssDNA coverage, the ionic strength, the nature of the thiol derivative and especially the Debye length are shown to have a significant impact on the impedance spectra. A mixed monolayer comprising--in addition to the ssDNA capture probe--both mercaptohexanol (MCH) and mercaptopropionic acid (MPA) is suggested as an interface design which allows a high efficiency of the DNA hybridization concomitantly with a reliable modulation of the charge-transfer resistance of the electrode upon hybridization.
Gebala
Magdalena
M
Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
Schuhmann
Wolfgang
W
D015097:3-Mercaptopropionic Acid / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D000441:Hexanols / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties
D000441:Hexanols; D013438:Sulfhydryl Compounds; D004247:DNA; D015097:3-Mercaptopropionic Acid; C477019:3-mercaptohexanol