Most wet organic or biological materials will produce memristive (pinched hysteresis) IV curves when measured with macroelectrodes (1–20 mm contact scale) due to inherent interfacial electrochemistry, ion migration, or redox processes at the electrode-tissue interface.
Macroscale memristivity is an artifact of slow interfacial kinetics sampled over large diffusion volumes. Shrink electrodes below ~100 µm → hysteresis vanishes.
Dry biological materials almost never show true memristive (pinched, history-dependent) IV curves at any electrode scale (macro or micro) under standard DC sweeps. The reasons are structural and physicochemical—drying eliminates the ionic mobility that sustains memory.
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