We love it when scientists look to the natural world for design inspiration – whether they are creating a robot based on the cheetah or vehicles that can jump like a sand flea. Inspired by the mimicry ability of creatures such as the squid and zebrafish, a team from Bristol University recently created a new type of artificial muscles made from ‘smart cells’ that can camouflage themselves. The team believes the muscles can be used in everything from medical devices to color-changing ‘smart clothing’.

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The team led by Dr Jonathan Rossiter from the Department of Engineering Mathematics and Dr Andrew Conn, Lecturer in the Department of Mechanical Engineering recently published their research in IOP Publishing’s journal Bioinspiration and Biomimetics. “We have taken inspiration from nature’s designs and exploited the same methods to turn our artificial muscles into striking visual effects,” said lead author of the study Dr Jonathan Rossiter.

The team’s artificial muscles are based on specialist cells called chromatophores that are found in amphibians, fish, reptiles and cephalopods. They often contain pigments of colours that allow creatures, such as squid, to change colour depending on their mood, temperature or environment.

Two types of artificial chromatophores were created in the bio-mimicry study: the first based on a mechanism adopted by a squid and the second based on a rather different mechanism adopted by zebrafish. In a squid, a typical colour-changing cell has a central sac containing granules of pigment. When the cell wishes to change colour,  the brain sends a signal to the muscles surrounding it and they contract. The contracting muscles make the central sacs expand, generating an optical effect that makes the squid look like it is changing colour.

In the zebrafish, the cells  contain a small reservoir of black pigmented fluid that, when activated, travels to the skin surface and spreads out, much like the spilling of black ink.

The team duplicated these processes with dielectric elastomer (DE), a smart material that changes when a voltage is applied, but returns to its original shape once it is short circuited. The zebrafish’s camouflage ability was also replicated by using two glass microscope slides sandwiching a silicone layer. Two pumps, made from flexible DEs, were then positioned on both sides of the slide and were connected to the central system with silicone tubes; one pumping opaque white spirit, the other a mixture of black ink and water.

“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. 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,” continued Rossiter.

So there you go – the first step for mankind to gain the ability to camouflage itself? Or simply a technology that may one simply let us create clothing that lets us display our mood or hide from other people. The military might be interested in that…

+ Bristol University

via BBC News

Lead image: Dan Hershman