Hierarchically engineered nanochannel systems with pore-in/on-pore structures

Biological ion channels featuring asymmetries in structure, composition, and charge distribution have superior controllable ion transport properties, such as ion selectivity, ion gating, and ion rectification, by which life executes diverse activities, including signal transduction, cell motility, and mass and energy transfer. Inspired by this, researchers have never stopped pursuing artificial ion channels that can achieve comparable functions. Despite successful explorations in many fields, current homogeneous nanochannels, however, have not yet offered sufficient rewards comparable to those of their natural counterparts. However, hierarchically engineered heterogeneous nanochannels have gradually come onto the stage because of their excellent ion selectivity, permeability, and rectification properties and thus have been shining brilliantly in fields such as selective ion transport, energy conversion, biomolecular separation, and detection. In this article, we briefly review the recent advances of hierarchically engineered nanochannel systems in terms of pore-on-pore and pore-in-pore structures, with an emphasis on promising applications, including ion-selective transport, osmotic energy harvesting, separation, and biosensing. Finally, current challenges and conceivable solutions are also discussed to advance the design and applications of hierarchical nanochannel systems.

Automated summary

Biological ion channels have asymmetries in structure and charge distribution, which enable them to perform diverse activities such as signal transduction and cell motility. Inspired by this, researchers have been pursuing artificial ion channels with comparable functions. However, current homogeneous nanochannels have not been able to achieve similar rewards. Hierarchically engineered heterogeneous nanochannels, on the other hand, have shown promising properties such as ion selectivity and permeability, and have found applications in selective ion transport, energy conversion, biomolecular separation, and detection. In this article, recent advances in these hierarchically engineered nanochannel systems are reviewed, with a focus on pore-on-pore and pore-in-pore structures, and their potential applications are discussed.