Ultra-Thin Colour Changing Films Made From Squid Skin

Octopuses, squids, cuttlefishes and other members of the family of the cephalopods are true masters of disguise. Their ability to camouflage themselves and become nearly invisible in a matter of seconds is quite unique on earth. By now, scientist were not able to replicate that skill or to create something comparable. But recently, Leila Deravi, assistant professor of chemistry and chemical biology at Northeastern University, Boston took the research in this field to the next level and the results might also benefit the printing industry.

The Power of Colour Changing Organs

The chromatophore organs of the cephalopods appear as hundreds of multi-coloured freckles on the body surface and contribute to the ability of fast changing the skin colour. Deravi and her research group described in a paper, published in Advanced Optical Materials, how they isolate the pigment granules within the organs to better understand the function. In doing so, they discovered the remarkable optical qualities of these granules and were able to create thin films and fibers, which could be implanted into textiles, flexible displays and other devices. Chromatophores come in different shades of red, yellow, brown and orange, similar to freckles on human skin. But in the case of cephalopods, the freckles open and close within a matter of a second. This enables the animals to continuously reconfigure their skin colour. Furthermore, there is a layer of iridophores underneath the chromatophores, acting like a mirror. Together, these organs reflect all colours of visible light. To explore the breadth of the capabilities as static materials, the team removed individual pigments from squids and tested their composition and structure.

“We’re showing these pigments are a powerful tool that can produce ultra-thin films that are really rich in colors,”

Deravi said.

Hightech Made from Squid Skin

The researchers made spools of fibers from the pigments and tested their use for new materials. Next to weaving them into fabric for clothing, the most exciting possibility is to create wearable, flexible screens and textiles that are able of adaptive colouration. The team also discovered that the pigments can scatter both visible and infrared light. This is important for the brightness and light absorption and affect the final colour. In a test system, the team mimicked the layout of organs that squids naturally have. So they were able to further enhance the perceived colour through scattering light trough and off the granules. This process could be theoretically replicated on more functional materials like solar cells to increase the absorption of sunlight. It is conceivable that also whole new kinds of packaging and print products, for example with colour changing abilities, might emerge from these research results.

“From a scientific and technical engineering perspective, understanding how light scattering affects color is very important, and this is an exciting new development in the field of optics in biology,”

said Richard Osgood, a collaborator from the U.S. Army Natick Soldier Research, Development, and Engineering Center.

“This is an unusual harnessing of optics and physics knowledge in scattering to understand biological systems.”

Not Yet Done

Also many scientists aimed to replicate the abilities of squid skin, most of them never come near the speed and dynamic range of colour, the animals can display. Leila Deravi and her team made some major advantages in research in the last years, but there is still a long road ahead them, until this technology becomes ready for production.

Where do you see efficient application possibilities for a possible squid based technology? We’re looking forward to discuss with you!