Scientists have created a fully biodegradable artificial synapse using chitosan from crab shells, plant fibers, and bean extracts. The device operates at just 0.85 femtojoules per signal, making it more efficient than the human brain while retaining memory for nearly 100 minutes (the longest ever for biodegradable synapses). The breakthrough potentially paves the way for AI hardware that learns, adapts, and dissolves without toxic waste.