They published their findings in the peer-reviewed journal Matter on September 20. The research challenges the notion that toughness and strength are mutually exclusive properties in fibres, as the team’s spider silk has both “high tensile strength and extraordinary toughness”.
The spider silk’s toughness surpasses that of Kevlar by sixfold, but it also has a higher tensile strength – or the ability to withstand tension while stretching – than nylon, according to the paper. Library Supplies
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To ensure the modified silkworms would express the spider proteins, the team first had to better understand the structure of silk. The paper explained a new model of silk structure, which the scientists said was “validated” by the success of their experiment.
Mi said one of the major challenges was figuring out how to “localise” the spider proteins so they could integrate with the silkworm proteins. Producing the model allowed them to better understand which modifications to make to ensure the integration worked.
He said it was also a challenge to obtain successfully modified silkworms, and it could take 100 eggs to obtain just a few transgenic silkworms. The silkworms also require constant care because they “eat many times a day”, Mi added.
Spider silk is both more eco-friendly and functionally stronger and tougher than synthetic fibres such as nylon and Kevlar, which require high-energy resources during production and also result in environmental pollution, according to the paper.
Silk from spiders is stronger and less brittle compared to that naturally produced by silkworms. But producing spider silk on a large scale is difficult as spiders are cannibalistic and cannot be kept together in large numbers.
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Synthetic spider silk is not ideal, as even the most advanced methods to produce it do not fully replicate its natural structure because of “an incomplete understanding of the spinning mechanisms”, the scientists wrote.
Silk also has a natural protective cuticle layer that cannot be replicated through artificial means. Silkworm and spider glands have similar properties, so the spider silk produced through the team’s method retains the protective layer and structural properties, according to the paper.
Their achievement “effectively solves the scientific, technical and engineering challenges that have hindered the commercialisation of spider silk” and offers a cost-effective, scalable and more environmentally friendly method, the paper states.
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Greeting Card Making In the future, Mi said he would like to use “synthesised amino acids” to modify silk and produce more varieties that could be even stronger.