Nature Communications<\/em><\/a>.<\/p>\nFor many years, Professor Tuomas Knowles in Cambridge\u2019s Yusuf Hamied Department of Chemistry has been researching the behaviour of proteins. Much of his research has been focused on what happens when proteins misfold or \u2018misbehave\u2019, and how this relates to health and human disease, primarily Alzheimer\u2019s disease.<\/p>\n
\u201cWe normally investigate how functional protein interactions allow us to stay healthy and how irregular interactions are implicated in Alzheimer\u2019s disease,\u201d said Knowles, who led the current research. \u201cIt was a surprise to find our research could also address a big problem in sustainability: that of plastic pollution.\u201d<\/p>\n
As part of their protein research, Knowles and his group became interested in why materials like spider silk are so strong when they have such weak molecular bonds. \u201cWe found that one of the key features that gives spider silk its strength is the hydrogen bonds are arranged regularly in space and at a very high density,\u201d said Knowles.<\/p>\n
Co-author Dr Marc Rodriguez Garcia, a postdoctoral researcher in Knowles\u2019 group who is now Head of R&D at Xampla, began looking at how to replicate this regular self-assembly in other proteins. Proteins have a propensity for molecular self-organisation and self-assembly, and plant proteins, in particular, are abundant and can be sourced sustainably as by-products of the food industry.<\/p>\n
\u201cVery little is known about the self-assembly of plant proteins, and it\u2019s exciting to know that by filling this knowledge gap we can find alternatives to single-use plastics,\u201d said PhD candidate Ayaka Kamada, the paper\u2019s first author.<\/p>\n
The researchers successfully replicated the structures found on spider silk by using soy protein isolate, a protein with a completely different composition. \u201cBecause all proteins are made of polypeptide chains, under the right conditions we can cause plant proteins to self-assemble just like spider silk,\u201d said Knowles, who is also a Fellow of St John’s College. \u201cIn a spider, the silk protein is dissolved in an aqueous solution, which then assembles into an immensely strong fibre through a spinning process which requires very little energy.\u201d<\/p>\n
\u201cOther researchers have been working directly with silk materials as a plastic replacement, but they\u2019re still an animal product,\u201d said Rodriguez Garcia. \u201cIn a way, we\u2019ve come up with \u2018vegan spider silk\u2019 \u2013 we\u2019ve created the same material without the spider.\u201d<\/p>\n
Any replacement for plastic requires another polymer \u2013 the two in nature that exist in abundance are polysaccharides and polypeptides. Cellulose and nanocellulose are polysaccharides and have been used for a range of applications, but often require some form of cross-linking to form strong materials. Proteins self-assemble and can form strong materials like silk without any chemical modifications, but they are much harder to work with.<\/p>\n
The researchers used soy protein isolate (SPI) as their test plant protein, since it is readily available as a by-product of soybean oil production. Plant proteins such as SPI are poorly soluble in water, making it hard to control their self-assembly into ordered structures.<\/p>\n
The new technique uses an environmentally friendly mixture of acetic acid and water, combined with ultrasonication and high temperatures, to improve the solubility of the SPI. This method produces protein structures with enhanced inter-molecular interactions guided by the hydrogen bond formation. In a second step, the solvent is removed, which results in a water-insoluble film.<\/p>\n
The material has a performance equivalent to high-performance engineering plastics such as low-density polyethylene. Its strength lies in the regular arrangement of the polypeptide chains, meaning there is no need for chemical cross-linking, which is frequently used to improve the performance and resistance of biopolymer films. The most commonly used cross-linking agents are non-sustainable and can even be toxic, whereas no toxic elements are required for the Cambridge-developed technique.<\/p>\n
\u201cThis is the culmination of something we\u2019ve been working on for over ten years, which is understanding how nature generates materials from proteins,\u201d said Knowles. \u201cWe didn\u2019t set out to solve a sustainability challenge — we were motivated by curiosity as to how to create strong materials from weak interactions.\u201d<\/p>\n
\u201cThe key breakthrough here is being able to control self-assembly, so we can now create high-performance materials,\u201d said Rodriguez Garcia. \u201cIt\u2019s exciting to be part of this journey. There is a huge, huge issue of plastic pollution in the world, and we are in the fortunate position to be able to do something about it.\u201d<\/p>\n
Xampla’s technology has been patented by Cambridge Enterprise, the University’s commercialisation arm. Cambridge Enterprise and Amadeus Capital Partners co-led a \u00a32 million seed funding round for Xampla, joined by Sky Ocean Ventures and the University of Cambridge Enterprise Fund VI, which is managed by Parkwalk.<\/p>\n
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Reference<\/h3>\n
A. Kamada et al. \u2018Self-assembly of plant proteins into high-performance multifunctional nanostructured films.\u2019 Nature Communications<\/em> (2021). DOI: 10.1038\/s41467-021-23813-6<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"The researchers, from the University of Cambridge, created a polymer film by mimicking the properties of spider silk, one of the strongest materials in nature. The new material is as strong as many common plastics in use today and could replace plastic in many common household products. The material was created using a new approach […]<\/p>\n","protected":false},"author":59,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","nova_meta_subtitle":"","footnotes":""},"categories":[5572],"tags":[5847,12239,13747,13831],"supplier":[1311],"class_list":["post-90260","post","type-post","status-publish","format-standard","hentry","category-bio-based","tag-bioplastics","tag-compostability","tag-film","tag-spidersilk","supplier-university-of-cambridge-uk"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/90260","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/59"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=90260"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/90260\/revisions"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=90260"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=90260"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=90260"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=90260"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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