From symmetric to asymmetric design of bio-inspired smart single nanochannels

Biological nanochannels, such as ion channels and ion pumps, existing in cell membranes and intelligently controlling ions through the cell membrane serve as a big source of bio-inspiration for the scientists to build artificial functional nanochannels. In this Feature Article, a general strategy for the design and synthesis of bio-inspired smart single nanochannels is presented, and put into context with recent progress in constructing symmetric and asymmetric smart single polymer nanochannels with single/double artificial gates which can respond to single/multiple external stimuli, e. g., pH, ions, temperature, light, and molecules. This article is intended to utilize specific stimulus-dependent ionic transport properties inside the single nanochannel as an example to demonstrate the feasibility of the design strategy, and provide an overview of this fascinating research field.