Protochromic Devices from a Cephalopod Structural Protein

Abstract Cephalopods possess remarkable camouflage capabilities, which are enabled by their complex innervated skin architectures and advanced nervous systems. As such, cephalopod skin constitutes an exciting model for biomimetic camouflage technologies. This study draws inspiration from the constituent components of optically active ultrastructures found in squid skin cells to help design color‐changing bioelectronic devices, which consist of a proton‐transporting active layer contacted by a proton‐conducting actuating electrode. The devices exhibit distinct shifts in their reflectance and coloration, which are attributed to active layer thickness changes induced by the direct electrical injection/extraction of protons. The reported findings may hold relevance for developing novel color‐changing technologies, understanding ion‐transporting biological systems, and engineering improved bioelectronic platforms.