Short-Term Facilitation-Then-Depression Enables Adaptive Processing of Sensory Inputs by Ion Channels in Biomolecular Synapses

Providing AI platforms with perceptual capabilities at low energy cost is imperative to making them more human-like. This goal is contingent on developing stimuli-responsive materials that closely emulate diverse synaptic functions needed to enhance machine learning applications. Here a biomolecular device is reported, consisting of an insulating lipid membrane doped with voltage-activated, ion channel-forming monazomycin (Mz) species, that display diode-like current-voltage characteristics and emulate short-term facilitation-then-depression on time scales relevant to habituation in human sensory systems. Subjected to a slow train of voltage pulses, devices show only facilitation upon Mz channel formation. At higher pulse rates, faster facilitation creates later depression upon Mz inactivation. The device is integrated as a biomolecular synapse in an organic-inorganic hybrid afferent model to demonstrate its ability to process sensory inputs and mimic bidirectional retinal adaptation and sensitization. These findings highlight the value of instilling complex synaptic plasticity into engineered systems, which is useful for adaptive neuroprosthetics and biosignal processing.