Chemically Gated Reconfigurable Nanofluidic Synapse Enables Metaplasticity and Neuromorphic Sound Recognition

Metaplasticity, the adaptive regulation of synaptic plasticity, is fundamental to biological information processing but remains challenging to implement in artificial systems, especially in fluidic environments. Herein, we address this challenge by developing a graphene oxide-based nanofluidic synapse capable of reconfigurable plasticity, where synaptic plasticity can be reversibly regulated via extrinsic ionic cues. Specifically, modulating the electrolyte's trivalent Y3+ ion concentration allows the device to be switched among diverse synaptic plasticity forms within one physical architecture. Combined experimental and theoretical analyses indicate that Y3+ migration on the nanochannel surface modulates the surface charge, thereby gating K+ and Cl- transport kinetics and enabling tunable synaptic dynamics. Consequently, Y3+ concentration acts as a prior contextual signal that preconditions the synaptic response to subsequent electrical stimuli and implementing chemically gated metaplasticity. Finally, using devices with complementary plasticity, we demonstrate a neuromorphic sound recognition system that achieves substantially higher accuracy than one using uniform synapses.