Squid could provide an eco-friendly alternative to plastics

February 21, 2019, Frontiers
Credit: CC0 Public Domain

The remarkable properties of a recently-discovered squid protein could revolutionize materials in a way that would be unattainable with conventional plastic, finds a review published in Frontiers in Chemistry. Originating in the ringed teeth of a squid's predatory arms, this protein can be processed into fibers and films with applications ranging from 'smart' clothes for health monitoring, to self-healing recyclable fabrics that reduce microplastic pollution. Materials made from this protein are eco-friendly and biodegradable, with sustainable large-scale production achieved using laboratory culture methods.

"Squid proteins can be used to produce next generation for an array of fields including energy and biomedicine, as well as the security and defense sector," says lead author Melik Demirel, Lloyd and Dorothy Foehr Huck Endowed Chair in Biomimetic Materials, and Director of Center for Research on Advanced Fiber Technologies (CRAFT) at Penn State University, USA. "We reviewed the current knowledge on squid ring teeth-based materials, which are an excellent alternative to plastics because they are eco-friendly and environmentally sustainable."

Squid ring teeth are all-rounders

As humanity awakens to the aftermath of a 100-year party of plastic production, we are beginning to heed nature's warnings—and its solutions.

"Nature produces a variety of smart materials capable of environmental sensing, self-healing and exceptional mechanical function. 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," explains Demirel.

The oceans, which have borne the brunt of plastic pollution, are at the center of the search for sustainable alternatives. A newly-discovered protein from squid ring teeth (SRT) - circular predatory appendages located on the suction cups of squid, used to strongly grasp prey—has gained interest because of its remarkable properties and sustainable production.

The elasticity, flexibility and strength of SRT-based materials, as well as their self-healing, optical, and thermal and electrical conducting properties, can be explained by the variety of molecular arrangements they can adopt. SRT proteins are composed of arranged in such a way that micro-phase separation occurs. This is a similar situation to oil and water but on a much smaller, nano-scale. The blocks cannot separate completely to produce two distinct layers, so instead molecular-level shapes are created, such as repeating cylindrical blocks, disordered tangles or ordered layers. The shapes formed dictate the property of the material and scientists have experimented with these to produce SRT-based products for a variety of uses.

In the textiles industry, SRT protein could address one of the main sources of microplastic pollution by providing an abrasion-resistant coating that reduces microfiber erosion in washing machines. Similarly, a self-healing SRT coating could increase the longevity and safety of damage-prone biochemical implants, as well as garments tailored for protection against chemical and biological warfare agents.

It is even possible to interleave multiple layers of SRT proteins with other compounds or technology, which could lead to the development of 'smart' clothes that can protect us from pollutants in the air while also keeping an eye on our health. The optical properties of SRT-based materials mean these clothes could also display information about our health or surroundings. Flexible SRT-based photonic devices—components that create, manipulate or detect light, such as LEDs and optical displays, which are typically manufactured with hard materials like glass and quartz—are currently in development.

"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.

No squid was harmed in the making of this film

One of the main advantages of SRT-based materials over synthetic materials and plastics made from fossil fuels are its eco-credentials. SRT proteins are cheaply and easily produced from renewable resources and researchers have found a way of producing it without catching a squid."We don't want to deplete natural 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," explains Demirel.

It is hoped that the SRT-based prototypes will soon become available more widely, but more development is needed.

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

Explore further: Tiny fibers create unseen plastic pollution

More information: Frontiers in Chemistry, DOI: 10.3389/fchem.2019.00069 , https://www.frontiersin.org/articles/10.3389/fchem.2019.00069/full

Related Stories

Tiny fibers create unseen plastic pollution

February 17, 2019

While the polyester leisure suit was a 1970s mistake, polyester and other synthetic fibers like nylon are still around and are a major contributor to the microplastics load in the environment, according to a Penn State materials ...

Repetition key to self-healing, flexible medical devices

February 8, 2018

Medical devices powered by synthetic proteins created from repeated sequences of proteins may be possible, according to materials science and biotechnology experts, who looked at material inspired by the proteins in squid ...

Programmable materials find strength in molecular repetition

May 23, 2016

Synthetic proteins based on those found in a variety of squid species' ring teeth may lead the way to self-healing polymers carefully constructed for specific toughness and stretchability that might have applications in textiles, ...

Water heals a bioplastic

September 1, 2015

A drop of water self-heals a multiphase polymer derived from the genetic code of squid ring teeth, which may someday extend the life of medical implants, fiber-optic cables and other hard to repair in place objects, according ...

Recommended for you

Machine learning identifies links between world's oceans

March 21, 2019

Oceanographers studying the physics of the global ocean have long found themselves facing a conundrum: Fluid dynamical balances can vary greatly from point to point, rendering it difficult to make global generalizations.

How fluid viscosity affects earthquake intensity

March 21, 2019

Fault zones play a key role in shaping the deformation of the Earth's crust. All of these zones contain fluids, which heavily influence how earthquakes propagate. In an article published today in Nature Communications, Chiara ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Squiddles
not rated yet Feb 21, 2019
Nice article, but the animal on the main photo is not a squid, it's an octopus. That might be of minor importance in some contexts (since, at least, they are both cephalopods), but octopuses don't actually have rings on their suckers. Which is the crux of the whole story, right? ;)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.