Color Changing Mechanisms of Cephalopods Used in Developing Color Changing Materials

Cephalopods, including squids and octopuses, are renowned for their exceptional ability to alter their color, an adaptation that serves purposes ranging from camouflage to communication. This review examines the underlying mechanisms of color change in cephalopods and explores how these biological processes have been applied to develop advanced, bio-inspired materials with tunable optical properties. Cephalopods employ three main cellular structures-chromatophores, iridophores, and leucophoreseach contributing to distinct aspects of coloration and light manipulation. Chromatophores, containing pigment-filled sacs, enable rapid color changes through muscular contractions, while iridophores and leucophores manipulate light through structural changes. Recent advancements in the understanding of these mechanisms have led to the development of biomimetic materials that replicate cephalopod coloration. These include tunable photonic coatings, polymer composites, and nanostructures inspired by reflectin proteins, which are key to the cephalopods' ability to dynamically adjust their appearance. Such innovations hold promise for applications in adaptive camouflage, responsive displays, and bio-inspired sensors. This review highlights the current state of research on cephalopod color-changing systems and discusses future directions for biomimetic materials inspired by these remarkable organisms.