DNA-modified electrodes, using DNA-mediated charge transfer, allow for the electrochemical detection of perturbations to the p-stack as subtle as single-base mismatches.  The coupling of the redox reporter to the p -stack is essential for accurate reporting of these subtle p-stack perturbations.  Covalently tethering Methylene Blue (MB) to DNA through a flexible alkyl linker is shown to yield a redox signal that is DNA-mediated and is 3 fold larger than previously employed reporters.  The signal enhancement achieved is attributed to MB interacting with the p-stack through intercalation.  Intercalation of the redox reporter is also shown to be more robust to different buffer conditions and have a higher degree of sensitivity towards p-stack perturbations.  The sensitivity of these DNA-modified electrodes are even further improved through the application of electrocatalytic signal amplification.  The signal obtained from MB modified DNA is electrocatalytically amplified by various electron sinks, including ferricyanide and hemoglobin.

Enhanced DNA electrochemistry through improved coupling to the π–stack and electrocatalysis

243rd National Meeting (2012)

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