Effective thermal management is critical for the operation of many modern technologies, such as electronic circuits, smart clothing, and building environment control systems. By leveraging the static infrared-reflecting design of the space blanket and drawing inspiration from the dynamic color-changing ability of squid skin, we have developed a composite material with tunable thermoregulatory properties. Our material demonstrates an on/off switching ratio of ~25 for the transmittance, regulates a heat flux of ~36 W/m 2 with an estimated mechanical power input of ~3 W/m 2 , and features a dynamic environmental setpoint temperature window of ~8 °C. Moreover, the composite can manage one fourth of the metabolic heat flux expected for a sedentary individual and can also modulate localized changes in a wearer’s body temperature by nearly 10-fold. Due to such functionality and associated figures of merit, our material may substantially reduce building energy consumption upon widespread deployment and adoption.

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.

Cephalopods have recently emerged as a source of inspiration for the development of novel functional materials. Within this context, a number of studies have explored structural proteins known as reflectins, which play a key role in cephalopod adaptive coloration in vivo and exhibit interesting properties in vitro. Herein, we report an improved high-yield strategy for the preparation and isolation of reflectins in quantities sufficient for materials applications. We first select the Doryteuthis (Loligo) pealeii reflectin A2 (RfA2) isoform as a "model" system and validate our approach for the expression and purification of this protein. We in turn fabricate RfA2-based twoterminal devices and employ both direct and alternating current measurements to demonstrate that RfA2 films conduct protons. Our findings underscore the potential of reflectins as functional materials and may allow a wider range of researchers to investigate their properties.Cephalopods (squid, octopuses, and cuttlesh) are well known for their sophisticated neurophysiology, complex behavior, and stunning camouage displays.1-6 Recently, these animals have drawn signicant attention as sources of novel materials for optical systems, 7-10 biomedical technologies, 11-15 and bioelectronic devices. [16][17][18][19][20] Within this context, a number of literature reports have investigated the properties of unique structural proteins known as reectins, [7][8][9][10]14,[16][17][18][21][22][23][24] which are found in cephalopod skin cells (i.e. leucophores, iridophores, and chromatophores). [25][26][27][28][29][30] In vivo, reectins in general have been shown to play important roles in cephalopod adaptive coloration by serving as components of optically-active ultrastructures, including layered stacks of membrane-enclosed platelets in iridophores, 25,26 membrane-bound arrangements of spherical microparticles in leucophores, 27,28 and interconnected networks of pigment granules in chromatophores. 29,30 In vitro, the Doryteuthis (Loligo) pealeii reectin A1 (RfA1) isoform has found applications in recongurable infrared camouage coatings that are actuated by chemical and mechanical stimuli, 7,8 proton-conducting lms with electrical gures of merit rivaling those of some articial analogues, 16-18 and biocompatible substrates that support the proliferation and differentiation of neural stem cells.14 Overall, reectins' fascinating properties have provided a strong impetus for their continued exploration from both fundamental and applied perspectives.Herein, we describe an improved methodology for the production of difficult-to-handle reectins in quantities sufficient for materials applications. We rst select the Doryteuthis (Loligo) pealeii reectin A2 (RfA2) isoform as a "model" system for electrical characterization and validate a new high-yield strategy for the expression and purication of this precipitation-prone protein. We subsequently fabricate and characterize two-terminal devices for which RfA2 thin lms constitute the active layer. We in tu...