A new material, dubbed “vegan spider silk”, has been created by researchers at the University of Cambridge and may be a long-term replacement for single-use plastic.
Human reliance on plastic remains one of the biggest environmental concerns, with millions of tons of waste produced every year. Tiny fragments, called microplastics, have been found atop the Alps and Himalayas, as well as at the bottom of the Pacific Ocean’s Mariana Trench and in Antarctica.
As a result of this increasingly urgent problem there is now a major push to find ways to break down existing plastic and create packaging to replace the ubiquitous oil-based plastics.
Cambridge researchers aiming to solve the second problem took inspiration from spider silk, one of nature’s strongest and most remarkable materials.
They identified that despite the molecular bonds holding spider silk together being weak, they were robustly reinforced with a high density of other bonds.
But animal-based proteins have their own difficulties and offer issues when it comes to scaling up for commercial use on ethical grounds.
Dr Tuomas Knowles, from Cambridge’s Yusuf Hamied Department of Chemistry, is an expert in protein folding and normally studies them to learn about the impact of misshapen proteins on human health.
But his expertise revealed what it is about spider silk that gives it immense strength. The team of academics were then able to apply this to a plant protein, derived from soy.
Soy is a widely farmed crop and its waste is readily available, but its proteins are extremely different to those of spider silk. Dr Knowles and his team however, were able to strip the soy protein back and reform it into the shape of spider silk.
“Because all proteins are made of polypeptide chains, under the right conditions we can cause plant proteins to self-assemble just like spider silk,” Dr Knowles said.
This method, which has been published in the journal Nature Communications, allows material scientists to avoid having to work with animal proteins.
“In a way we’ve come up with ‘vegan spider silk’ – we’ve created the same material without the spider,” said study co-author Dr Marc Rodriguez Garcia. He is also head of research and development at a company called Xampla which is working on commercialising the product.
Xampla says it will release a range of sachets and capsules by the end of 2021 which will replace products like dishwasher tablet wrappers and laundry capsules.
This plastic substitute is not only made from sustainable sources, but it can be left on a domestic compost heap and needs no special treatment to recycle it.
Cost, as with all new technologies, is the main issue facing widespread adoption of the technology.
The two-step process of reforming the proteins into the desired guse involves acidification, applying sound waves and high temperatures and this makes the cost of production akin to that of other natural plastic alternatives.