The layers of a protein called reflectin allow a squid to rapidly change its skin color and blend in with its surroundings have been applied by scientists to a sticky tape, so that the tape appears invisible under near-infrared light. The main application for the squid protein stickers could be to shield soldiers from detection by night-vision cameras.
Reflectin is a protein originating from the Hawaiian Bobtail Squid, Euprymna scolopes, which is native to the central Pacific Ocean. This protein is found in iridocytes, which are special cells in squid skin. These cells are composed of sheets of reflectin and they display different colors depending on the spacing between the light-reflecting layers.
Scientists from the University of California, Irvine, have managed to harness this natural property by coating bacterially expressed reflectin onto a hard surface. The scientists found that the color reflected by the protein layer depended on the thickness of the film. The surface’s color could also be altered by spraying it with vinegar vapors, which caused the previously visible layer to swell and appear invisible under infrared light.
Using this principle, scientists coated the protein on a pliable surface of tape that can change color when stretched. Discussing this further in a research note, lead author Alon Gorodetsky said: “We’re going after something that’s inexpensive and completely disposable. You take out this protein-coated tape, you use it quickly to make an appropriate camouflage pattern on the fly, then you take it off and throw it away.”
Before the technology can be applied to nighttime uniforms, the scientists need to modify the process further in order to increase its brightness and find a way to coordinate the pieces of tape so that they all reflect the correct wavelength.
The findings were presented at the American Chemical Society’s annual meeting held in Denver, which took place at the end of March 2015.