Label‐Free Electrochemical Recognition of DNA Hybridization by Means of Modulation of the Feedback Current in SECM

Stranded on the surface: The modulation of the amperometric feedback current in scanning electrochemical microscopy (SECM) through coulomb interactions between the phosphate groups of immobilized oligonucleotides and a freely diffusing, negatively charged redox mediator is used for imaging DNA spots (see picture) and establishing a simple and efficient label-free electrochemical detection of complementary hybridization on DNA microarrays.