Polysaccharide-based ionically active biomaterials for neuromorphic electronics: Molecular design, ion transport, and...

Neuromorphic electronics integrate state storage with signal transformation; nevertheless, a device that exhibits resistive switching is not inherently a neuromorphic element, necessitating a thorough investigation into how specific material structures dictate these functions. In this context, cellulose, chitosan, pectin, and starch are chemically distinct polysaccharides characterized by functional groups (hydroxyl, amino, and carboxyl), chain organization, counterions, and water content that can influence ion transport and electrode reactions. This review examines evidence from glycan chemistry and hydration to ion transport, switching mechanisms, and measured memory or synaptic responses. We compare two-terminal cells with electrolyte-gated devices and distinguish direct experimental demonstrations from unproven mechanistic interpretations. We also identify cases where reported values are not comparable because of differences in polymer composition, electrodes, humidity, and pulse protocols. The resulting framework emphasizes carbohydrate chemistry while treating device metrics and environmental lifetime as linked design outcomes. Finally, this review outlines a prioritized set of experiments designed to determine if molecular descriptors can predict ionic relaxation and device behavior under matched fabrication and measurement conditions.