Electronically controllable ion gating in biomimetic nanochannels

The stimulation induced by the change of extracellular or intracellular ionic concentration is a key factor in regulating the opening and closing of biological ion channels. However, the artificial nanochannel with gating control resembling the physiological ionic concentration remains underexplored. In this work, biconical nanochannels were fabricated in polyethylene terephthalate (PET) membranes through heavy-ion track etching and the dynamic regulation of voltage-gated ion transport was demonstrated. Systematic ionic conductance experiments with KCl, NaCl, CaCl 2 and MgCl 2 revealed asymmetric current–voltage characteristics mediated by the ion enrichment localized at the nanochannel tip. This ion accumulation driven by the applied electrical stimulation leads to an ionic gating behavior in the nanochannel which is dependent on the ion polarity and ion charge state. The enrichment of anion at the nanochannel tip induced a pronounced conductance suppression of up to 96%, the divalent cations significantly altered the gating response and enabled cation-dominated conduction, while the monovalent cation enrichment only induced marginal rectification change. This reversible electrical field regulation on the biomimetic nanochannel elucidates the voltage-dependent gating mechanism of biological ion channels and demonstrates a robust fabrication technique for dynamically tunable nanofluidic devices without chemical modification.