A researcher in the US has made a significant breakthrough in the fabrication of synthetic spider silk, paving the way for a new era of sustainable clothing production.
- Fuzhong Zhang, a professor of energy, environmental and chemical engineering at the McKelvey School of Engineering at Washington University in St Louis, has created new spider silk fusion proteins, called bi-terminal Mfp fused silks (btMSilks).
- Microbial production of btMSilks have eight-fold higher yields than recombinant silk proteins, and the btMSilk fibres have substantially improved strength and toughness while being lightweight.
- This could revolutionise clothing manufacturing by providing a more eco-friendly alternative to traditional textiles.
- The findings were published in Nature Communications.
The Context: Scientists have long been intrigued by the remarkable properties of spider silk, which is stronger than steel yet incredibly lightweight and flexible.
- The outstanding mechanical properties of natural spider silk come from its very large and repetitive protein sequence. However, it is extremely challenging to ask fast-growing bacteria to produce a lot of repetitive proteins.
The Research: Since engineering recombinant spider silk in 2018 using bacteria, Zhang has been working to increase the yield of silk threads produced from microbes while maintaining its desirable properties of enhanced strength and toughness.
- Higher yields will be critical if synthetic silk is to be used in everyday applications, particularly in the fashion industry where renewable materials are now much in demand.
- Zhang looked for disordered proteins that can be genetically fused to silk fragments to promote molecular interaction, so that strong fibres can be made without using large repetitive proteins. He found them in the work already been done on mussel foot proteins. Mussels secrete these specialised proteins on their feet to stick to things.
- Zhang and his collaborators have engineered bacteria to produce them and engineer them as adhesives for biomedical applications. Mussel foot proteins are also cohesive, which enables them to stick to each other well, too.
- By placing mussel foot protein fragments at the ends of his synthetic silk protein sequences, Zhang created a less repetitive, lightweight material that’s at least twice as strong as recombinant spider silk.
- The yields on Zhang’s material increased eight-fold compared with past studies, reaching 8 grams of fiber material from 1 litre of bacterial culture. This output constitutes enough fabric to test for use in real products.
What They Said:
The beauty of synthetic biology is that we have lots of space to explore. We can cut and paste sequences from various natural proteins and test these designs in the lab for new properties and functions. This makes synthetic biology materials much more versatile than traditional petroleum-based materials. Because our synthetic silk is made from cheap feedstock using engineered bacteria, it presents a renewable and biodegradable replacement for petroleum-derived fiber materials like nylon and polyester.
— Fuzhong Zhang
Professor of Energy, Environmental and Chemical Cngineering, McKelvey School of Engineering
Washington University in St Louis
