Bioinspired voltage-gated multi-state ion channels in MXene nanoconfinement for emulating synaptic plasticity
Biological ion channels exhibit multistate transport behavior beyond simple binary open-closed conformations, enabling dynamic control of neural signaling and transmembrane substance transport. Inspired by this, we synthesized a triphenylamine-ketone donor-acceptor (D-A) type poly(aryl amine-ketone) with multiple redox sites, allowing continuously tunable electrochemical states via hierarchical electron transfer. Combining this polymer with two-dimensional conductive MXene, we constructed a biomimetic nanofluidic transistor. Through side-group tuning to optimize redox matching, the polymer undergoes reversible conformation switching via intramolecular charge transfer at voltages below 1 V. The field-driven conformational changes induce electrostatic attraction, promoting reversible contraction of MXene interlayers. Synergistic coupling of interlayer spacing variation and dynamic interfacial charge rearrangement enables precise hierarchical control of ion flux. The device achieves three switchable ion transport states—closed, partially open, and fully open—with an ion switching ratio of 10 and outstanding cycling stability. Furthermore, synaptic plasticity features emulate fundamental attributes of biological signaling, providing a foundation for bioinspired neuromorphic devices.