Two-terminal protonic devices with PdHx proton conducting contacts and a Nafion channel achieve 25 ms spiking, short term depression, and low-energy memory switching.

The related concepts of disguising an object or physically changing it to resemble something entirely different have long captivated the human imagination. Although such notions are seemingly derived from fables and science fiction, cephalopods have perfected analogous capabilities over millions of years of natural evolution. Consequently, these invertebrates have emerged as exciting sources of inspiration for futuristic adaptive camouflage and shapeshifter-like technologies. Herein, we provide an overview of selected literature examples that have used cephalopods as models for the development of novel adaptive materials, devices, and systems. We in turn highlight some significant remaining challenges and potential future directions for such studies. Through this perspective, we hope to stimulate additional dialogue and continued scientific exploration within the area of cephalopod-inspired dynamic materials.

Films from the cephalopod protein reflectin demonstrate multifaceted functionality as infrared camouflage coatings, proton transport media, and substrates for growth of neural stem cells. A detailed study of the in vitro formation, structural characteristics, and stimulus response of such films is presented. The reported observations hold implications for the design and development of advanced cephalopod-inspired functional materials.

We highlight our recent efforts in developing devices that control the flow of H+ and OH− in biological polymers.

Cephalopods possess remarkable camouflage capabilities, which are enabled by their complex skin structure and sophisticated nervous system. Such unique characteristics have in turn inspired the design of novel functional materials and devices. Within this context, recent studies have focused on investigating the self-assembly, optical, and electrical properties of reflectin, a protein that plays a key role in cephalopod structural coloration. Herein, we report the discovery that reflectin constitutes an effective material for the growth of human neural stem/progenitor cells. Our findings may hold relevance both for understanding cephalopod embryogenesis and for developing improved protein-based bioelectronic devices.

This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world.

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.

Cephalopods (e.g., squid, octopuses, and cuttlefish) have long fascinated scientists and the general public alike due to their complex behavioral characteristics and remarkable camouflage abilities. As such, these animals are explored as model systems in neuroscience and represent a well-known commercial resource. Herein, selected literature examples related to the electrical properties of cephalopod-derived biopolymers (eumelanins, chitosans, and reflectins) and to the use of these materials in voltage-gated devices (i.e., transistors) are highlighted. Moreover, some potential future directions and challenges in this area are described, with the aim of inspiring additional research effort on ionic and protonic transistors from cephalopod-derived biopolymers.