Cephalopods (octopus, squid, and cuttlefish) master the art of camouflage and change their skin pigmentation instantly based on their environment. Knowing how they do it can help us develop new materials that vary in color depending on the light or our will. Very thin films or fibers could be created that would be integrated into clothing or flexible screens, for example.
We have known for decades that the color change of cephalopods is based on chromatophores, cells with pigments inside that reflect light, but very little is known about the photophysical processes underlying this phenomenon. Now, a work directed by Leila Deravi, professor of chemistry and biological chemistry at Northeastern University (Boston, United States), has discovered some of the keys to this modulation of colors refined by evolution over hundreds of millions of years. years.
Owners of color
The chromatophores of cephalopods are especially complex. They are distributed throughout its skin and are composed of a chromatophoric cell that houses the pigment granules in an elastic sac that the animal deforms through muscular contractions, so that the state of the pigments varies and with it the way in which they reflect all colors of visible light.
What Deravi and his team have done is isolate these pigment granules to better understand their role in this natural process, which could lay the groundwork for the creation of new color-changing materials. For example, camouflage clothing. It is not surprising that they have had the collaboration of researchers from the US Army.
Chromatophore granules are only 500 nanometers in size, 150 times less than the thickness of a human hair. The scientists isolated and rearranged them into layers, and found that in this way they produced a full range of colors by reflecting light. According to Deravi, “we are showing that these pigments are a powerful tool to produce ultra-thin films that are very rich in colors.”
Researchers have made coils of fabric from squid pigments and are exploring possible uses for this material, focusing primarily on adaptable colored textiles, which explains the interest of the US military.
Photo: The bobtail squid (Euprymna berryi) does not measure more than five centimeters. To camouflage itself it changes color and buries itself in the sand.
