Robust biodegradable synapse with sub-biological energy and extended memory for intelligent reflexive system

Area of Science:

• Materials Science
• Neuroscience
• Electronics Engineering

Background:

• Biodegradable artificial synapses are crucial for sustainable neuromorphic electronics.
• Current challenges include achieving long-term memory, low energy use, and mechanical stability simultaneously.

Purpose of the Study:

• To develop a fully biodegradable multilayer artificial synapse (M-AS) with enhanced memory and efficiency.
• To investigate the synaptic functionalities and potential applications of the M-AS.

Main Methods:

• Fabrication of a trilayer M-AS using crosslinked chitosan-guar gum (CS-GG) ion-active layers (IALs) and a cellulose acetate (CA) ion-binding layer (IBL).
• Utilizing sodium chloride as mobile ionic species for low-voltage ion migration and ion-dipole coupling (IDC) for memory formation.
• Characterization of synaptic functionalities including plasticity, memory encoding, and modulation under sub-millivolt operation.

Main Results:

• The M-AS demonstrated key synaptic functionalities: paired-pulse facilitation, short-term and long-term plasticity, multilevel memory encoding, and bidirectional modulation.
• Achieved the longest reported long-term memory time (5944 s) among biodegradable artificial synapses.
• Exhibited ultralow energy consumption (0.85 fJ/event), lower than biological synapses.
• Integrated into a bioinspired reflexive system for adaptive learning and reflex-like behaviors.

Conclusions:

• The developed M-AS offers a promising solution for sustainable neuromorphic electronics.
• The novel trilayer architecture and materials enable robust, efficient, and long-lasting artificial synaptic functions.
• Potential applications include low-power, intelligent human-machine interfaces and adaptive robotic systems.