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Breakthrough biogel for soft robots is made of such safe ingredients you can (technically) eat it

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Jun 22, 2020, 10:58 PM EDT (Updated)

Watching out for the environment is certainly something humans should take seriously. And as Wall-E proved, so should robots.

Soft robotics is the new frontier behind the grippers, sensors, and even artificial limbs of the future. The problem is that producing the stretchy yet strong materials needed for this type of equipment usually requires using fossil fuels that are not only toxic, but just keep getting dumped in landfills with other disposable tech. Now a team of scientists from the department of Soft Matter Physics and LIT Soft Materials Lab at Johannes Kepler University in Linz, Austira have created a revolutionary biogel made of completely nontoxic water-soluble materials, so not only is it biodegradable, but you could technically eat it. Not that you’d want to take a bite — but you could.

“Despite being entirely degradable when disposed in wastewater, our gels maintain their mechanical properties for more than one year under ambient conditions and enable soft actuators that operate for more than 330,000 cycles without failure,” the team notes in a recently published study in Nature Materials.

Their biogel is made of the same gelatin you might have for dessert, except without the strawberry flavor (though there is sugar involved). It has been a challenge to create natural materials for soft robotics because previous attempts have used environmentally safe materials that compromised strength and durability. Something made of gelatin sounds like it would fall apart in your fingers, but the new biogel is more durable and stretchable than you could imagine. The material is also self-adhering and can have any tears healed just by melting it back together with heat. It is inexpensive to produce compared to current materials used in soft robotics. Even better, it can disintegrate in water within five days.

Gelatin is a polymer, meaning that units in its molecules are chemically linked and keep repeating. Cellulose is another polymer used in the biogel for extra strength, since plants get their sturdy and fibrous walls from cellulose. Sugar was added for something other than flavor. It actually gives the substance super stretch, which makes sense when you think of something like taffy or caramel. Citric acid was used as an antibacterial agent. Glycerol — which is the star of those evil things otherwise known as triglycerides but is sweet and otherwise tasteless on its own — and water are also components whose amounts were adjusted until the scientists achieved a stable enough result. Other food-grade additives gave it a functional and structural boost.

What if a patient needs something made of this biogel inside their body long-term? Because the material degrades in H2O, if used alone, it would run the risk of creating blockage in the kidneys and other organs that provide filtration for the body. The scientists have a solution for that. It can be covered in water-resistant, but also biodegradable, shellac resins. Coated biogels were tested and showed that they wouldn't fall apart after immersion in water or acid. The only way to dissolve the coating is to soak it in a basic solution, such as calcium hydroxide that is also used to process corn, sugar, and fruit juice (not the toxic industrial stuff).

So far, the things that have been made out of this next-gen biogel range from sensors that look like gummy candy to an entire segment of an elephant’s trunk, which was one of the many strong but flexible structures in nature the biogel was inspired by. Some animals are notoriously difficult to give medication to because they don't trust people, so giving animals medicine with a familiar appendage like a trunk could work when human hands don’t. As this tech advances, it will keep getting closer and closer to replicating human skin.

“Our approach represents a frugal, environmentally benign and inexpensive route for future biodegradable technologies that avoid the incurrence of microplastics and are inherently safe when interacting with other life-forms,” the team said

But what about the flavor? The biogel hasn’t been taste-tested yet, but it sounds as if it would be somewhat sweet and citrusy. Still, you’re probably better off with a bag of gummies.


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