The cleanroom-free, cheap, and rapid fabrication of nanoelectrodes with low zM limits of detection

Nanoscale electrodes have been a topic of intense research for many decades. Their enhanced sensitivities, born out of an improved signal-to-noise ratio as electrode dimensions decrease, make them ideal for the development of low-concentration analyte sensors. However, to date, nanoelectrode fabrication has typically required expensive equipment and exhaustive, time-consuming fabrication methods that have rendered them unsuitable for widespread use and commercialization. Herein, a method of nanoband electrode fabrication using low cost materials and equipment commonly found in research laboratories around the world is reported. The materials' cost to produce each nanoband is less than €0.01 and fabrication of a batch takes less than 1 h. The devices can be made of flexible plastics and their designs can be quickly and easily iterated. Facile methods of combining these nanobands into powerful devices, such as complete three-electrode systems, are also displayed. As a proof of concept, the electrodes are functionalized for the detection of a DNA sequence specific to SARS-CoV-2 and found to display single molecule sensitivity.