Smart material made from squid teeth a potential plastic alternative

A newly-discovered material made from squid teeth could one day replace man-made fibres like nylon and polyester, according to a review by scientists at Pennsylvania State University. This would help to reduce microplastic pollution in the oceans, as well as paving the way for new possibilities such as self-repairing safety clothing, or garments with built-in, flexible screens.

The smart materials in question are made from a material found in the suckers on a squid’s tentacles. In some species, these suckers have a ring of ‘teeth’ to help the squid grip onto a surface. These are known as SRTs – squid ring teeth – and it’s the proteins they’re made of that have scientists excited.

SRT proteins are made up ‘building blocks’ that can combine in different ways to produce materials with different properties. Depending on the arrangement of the blocks, the material that results may be electrically conductive, or have self-healing properties, for instance.

"Nature produces a variety of smart materials capable of environmental sensing, self-healing and exceptional mechanical function,” said Melik Demirel, director of Penn State's Center for Research on Advanced Fiber Technologies, who led the research. “These materials, or biopolymers, have unique physical properties that are not readily found in synthetic polymers like plastic. Importantly, biopolymers are sustainable and can be engineered to enhance their physical properties.”

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Microfibres becoming detached from items of clothing in the washing machine are currently one major source of microplastic pollution, whereas clothing coated with SRT protein-based materials would be more durable.

Similarly, self-healing smart materials could be used to manufacture better safety wear, such as hazmat suits, say the researchers. By using layers of different SRT materials, interwoven with other layers, you could even create garments that change colour when air pollution hits dangerous levels, or with a built-in, flexible display.

"SRT photonics are biocompatible and biodegradable, so could be used to make not only wearable health monitors but also implantable devices for biosensing and biodetection," adds Demirel.

Best of all, there's no cruelty to animals involved, either – the SRT proteins can be grown in a lab, using genetically modified E.coli bacteria, without needing to trouble the already dwindling squid population. Indeed, it's far more efficient to grow them from scratch than it would be to 'harvest' them from nature.

"We don't want to deplete natural squid resources, and hence we produce these proteins in genetically modified bacteria. The process is based on fermentation and uses sugar, water and oxygen to produce biopolymers," Demirel explains.

“Scaling up these materials requires additional work," he continues. "We are now working on the processing technology of these materials so that we can make them available in industrial manufacturing processes."

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