We report about new DNA hybridization assays with capture probes on gold electrodes allowing to use covalent osmium tetroxide bipyridine labels without a seperate modification step for the target strands. This has been achieved by using either signaling strands in a competitive assay, labeled reporter strands in a sandwich assay, or labeled PCR primers. Single base mismatches introduced to the capture probe section, or the reporter strand section, or both, could be discriminated, because of their different thermal hybridization behavior. The optimal hybridization time was 45 min. For the first time, our approach of protective strands has been applied to produce osmium tetroxide-labeled PCR primers. Polymerase tolerated the osmium labels after the removal of the protective strands by magnetic separation. Such approaches, where labeled primers, signaling or reporter strands have been prepared as bioanalytical reagents before the analysis, will save tremendous time and handling steps in real-world and even field application settings, while still providing the major advantages of the multiple labeling with reversible redox-markers that yield large voltammetric signals.

Electrochemical DNA hybridization detection based on reporter strands and primers labeled with osmium tetroxide

251st National Meeting (2016)

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