Iontronic Neuromorphic Signaling with Conical Microfluidic Memristors

TL;DR

This paper demonstrates that conical microfluidic channels filled with electrolyte exhibit iontronic memory effects due to concentration polarization, enabling neuromorphic circuits that mimic neuronal signaling.

Contribution

It introduces an analytic model for iontronic memristive behavior in conical channels and proposes a Hodgkin-Huxley circuit using these channels for neuromorphic applications.

Findings

Channels show history-dependent conductance due to concentration polarization.

The analytic model agrees well with finite-element simulations.

The proposed circuit reproduces neuronal features like action potentials.

Abstract

Experiments have shown that the conductance of conical channels, filled with an aqueous electrolyte, can strongly depend on the history of the applied voltage. These channels hence have a memory and are promising elements in brain-inspired (iontronic) circuits. We show here that the memory of such channels stems from transient concentration polarization over the ionic diffusion time. We derive an analytic approximation for these dynamics which shows good agreement with full finite-element calculations. Using our analytic approximation, we propose an experimentally realisable Hodgkin-Huxley iontronic circuit where micrometer cones take on the role of sodium and potassium channels. Our proposed circuit exhibits key features of neuronal communication such as all-or-none action potentials upon a pulse stimulus and a spike train upon a sustained stimulus.