|Chemical Engineers at the University of California, Irvine, US, developed a type of ‘invisibility sticker’ using squid skin proteins which could help soldiers to evade detection by enemy infrared cameras at night. Squid can change the colour of their skin to blend into their background. The skin contains cells called iriodocytes which contain layers of protein called reflectin. By using a biochemical process, the thickness of the reflectin can be changed, which changes the way it reflects light and therefore its colour. A team of researchers led by chemical engineering assistant professor Alon Gorodetsky has found a way to use reflectin to reflect infrared light as well as invisible light. His team engineered bacteria to produce reflectin, which they then coated onto polymer films much the same as sticky tape. Like with the squid, the colour of the stickers can be changed by varying the thickness of the reflectin. A thinner film looks blue, while a thicker film appears orange. The stickers can also be tuned to reflect near-infrared light. The team is now engineering the stickers to reflect mid- and far-infrared light, which will improve their ability to help
thwart infrared imaging cameras. They are also working to improve the brightness of the stickers and to ensure the stickers all respond in the same way, creating an adaptive camouflage system.