May 4, 2012
Squid And Zebrafish Spark Camouflage Inspiration
University of Bristol researchers have created artificial muscles that can be transformed to mimic the camouflaging abilities of squid and zebrafish.
The team demonstrated two individual transforming mechanisms that they believe could be used in "smart clothing" to trigger camouflaging tricks similar to animals observed in the wild.
"We have taken inspiration from nature's designs and exploited the same methods to turn our artificial muscles into striking visual effects," Jonathan Rossiter, lead author of the study published in the journal Bioinspiration and Biomimetics, said in a press release.
The artificial muscles are based on specialist cells known as chromatophores, which are found in amphibians, fish, reptiles and cephalopods. These cells contain pigments of colors that are responsible for the animals' color-changing effects.
The color changes in animals like the squid or zebrafish can be triggered by changes in mood, temperature, stress or something visible in the environment.
The researchers created two different types of artificial chromatophores during the study, the first of which is based on a mechanism adopted by a squid. The second artificial chromatophore made in the study is based on a mechanism used by the zebrafish.
A color-changing cell in a squid has a central that contains granules of pigment. This sac is surrounded by a series of muscles, and when the cell is ready to change color, the brain sends a signal to the muscles and they contract.
The contracting muscles make the central sacs expand, generating the optical effect which makes the squid look like it is changing color.
The researchers mimicked the expansion of these muscles using dielectric elastomers (Des), which are connected to an electric circuit and expand when a voltage is applied.
The cells in the zebrafish contain a small reservoir of black pigmented fluid that travels to the skin surface and spreads out, like the spilling of black ink.
The natural dark spots on the surface of the zebrafish appear to get larger, and optical effect can then be seen.
The zebrafish cells were mimicked by using two glass microscope slides that were sandwiching a silicone layer. The researchers used two pumps that were positioned on both sides of the slide and were connected to the central system with silicone tubes.
"Our artificial chromatophores are both scalable and adaptable and can be made into an artificial compliant skin which can stretch and deform, yet still operate effectively," Rossiter said in a press release.
"This means they can be used in many environments where conventional 'hard' technologies would be dangerous, for example at the physical interface with humans, such as smart clothing."