In nanopore analytics, individual molecules pass through a single nanopore giving rise to detectable temporary blockades in ionic pore current. Reflecting its simplicity, nanopore analytics has gained popularity and can be conducted with natural protein as well as man-made polymeric and inorganic pores. The spectrum of detectable analytes ranges from nucleic acids, peptides, proteins, and biomolecular complexes to organic polymers and small molecules. Apart from being an analytical tool, nanopores have developed into a general platform technology to investigate the biophysics, physicochemistry, and chemistry of individual molecules (critical review, 310 references).

The creation of synthetic devices that mimic functionality of biological systems is a task of fundamental importance for the future development of bio- and nanotechnology and also an ultimate test of our understanding of the biological systems. Among a plethora of bio-inspired devices, designed nanopores and nanochannels with an embedded functionality are of particular interest because of their potential applications in nanofluidic electronics, biosensing, separation, synthetic biology, and single-molecule manipulation. In this respect, nanopores with built-in stimulus-responsive properties are of special benefit. A transmembrane potential is a particularly useful stimulus as it is non-invasive, tunable, and can act over a short time scale. This critical review considers engineered solid-state and protein nanopores with voltage-responsive properties. The engineered systems show nonlinear current–voltage curves, and/or voltage-dependent switching between discrete conductance states (141 references).