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Professor Berni Kraatz, Department of Physical and Environmental Sciences, University of Toronto

Event Date: 
Monday, January 20, 2020 - 3:30pm to 4:30pm

Analytical applications of DNA-modified surfaces


The detection of biological analytes or of biochemical processes by electrochemical methods requires in many cases the presence of a redox-active probe as part of the detection system. The focus of this presentation is on the use of electrochemical methods to probe nucleic acids.

Here, thin films of DNA on gold surfaces are studied and their properties are probed using a range of electrochemical and spectroscopic tools.

Impedance spectroscopy and scanning electrochemical microscopy allows the detection of single nucleotide mismatches. This assay does not require any labeling of the target strand and relies on monitoring changes in charge transfer resistance of an external anionic redox probe as a function of a basepair mismatch within the double stranded DNA. The effect is caused by differences in the ability of the redox probe to diffuse into a DNA film. In this context, the use of scanning electrochemical microscopy is useful as current responses are limited by the re-generation of the redox mediator at the modified electrode surface. This allows the identification of basepair mismatches but also allows monitoring of metal-DNA interactions.


Event Location: 
Location Details: 
JHE 326H