Electrochemical Single-Molecule Detection in Aqueous Solution Using Self-Aligned Nanogap Transducers

Electrochemical detection of individual molecular tags in nanochannels may enable cost-effective, massively parallel analysis and diagnostics platforms. Here we demonstrate single-molecule detection of prototypical analytes in aqueous solution based on redox cycling in 40 nm nanogap transducers. These nanofluidic devices are fabricated using standard microfabrication techniques combined with a self-aligned approach that minimizes gap size and dead volume. We demonstrate the detection of three common redox mediators at physiological salt concentrations.