| STUDY |
Most DNA analysis relies on fluorescence detection, but electrochemistry could provide an alternative. Authors have electrochemically detected single-base mismatches and lesions on hybridized DNA with a technique they suggest could be used to diagnose mutations and single-nucleotide polymorphisms in a chip-based assay. Gold electrodes coated with preassembled DNA duplexes are used to detect the electrocatalytic reduction of methylene blue (a DNA intercalator) coupled to ferricyanide. Base mismatches and damaged DNA perturb the base stacking in the DNA duplexes and diminish the flow of charge through the film. Using the electrocatalytic assay, the researchers can distinguish all possible mismatches--including GA and GT, which are difficult to detect with other methods--from perfectly matched duplexes with high sensitivity, although it's not easy to tell one sort of mismatch from another.
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