Electrochemistry in nanopore/electrode structures - from pore fabrication to DNA sequencing-by-tunneling

Electrode/nanopore structures hold promise towards the fabrication, functionalization and control of nanopore sensor performance. This includes "simple" one-electrode structures, where an additional membrane electrode is used to control the electrostatic properties of the nanopore, but also more sophisticated two-electrode junction devices, integrating tunneling detection with nanopore-based singleDNA detection. Here we extend our previous work on this subject and extend the discussion towards potential “artefacts” during sensor operation, such redox amplification and capacitive re-charging of the tunneling junction. A detailed analysis shows that none of these is capable of reproducing the experimentally observed current modulation, supporting the notion that tunneling is indeed at the root of the observed effect. Ultimately, this is of key importance with a view on potential applications in tunneling-based single-molecule DNA sequencing applications.