Genetically Engineered Silkworms Spin Super Strong Partly-Spider Silk

Scientists have taken a new step towards mass-producing spider silk, an incredible material whose potential we haven’t been able to harness quite yet. From Not Exactly Rocket Science:

Spider silk is a remarkable material, wonderfully adapted for trapping, crushing, climbing and more. It is extraordinarily strong and tough, while still being elastic enough to stretch several times its original length. Indeed, the toughest biological material ever found is the record-breaking silk of the Darwin’s bark spider. It’s 10 times tougher than Kevlar, and the basis of webs that can span rivers.

Because of its enticing properties, spider silk has enormous potential. It could be put to all sorts of uses, from strong sutures to artificial ligaments to body armour. That is, if only we could make enough of the stuff. Farming spiders is out of the question. They are territorial animals with a penchant for eating each other. It took 82 people, 4 years and 1 million large spiders to make a piece of cloth just 11 feet by 4 feet…

As a large industry and centuries of history can attest to, silkworms are easy to farm in large numbers. And they’re silk-spinning machines, with massive glands that turn silk proteins into fibres…

Fraser had just the right tool for the job. In the 1980s, he identified pieces of DNA that can hop around insect genomes, cutting themselves out of one location and pasting themselves in somewhere else. He named them PiggyBac, and he has turned them into tools for genetic engineering. You can load PiggyBac elements with the genes of your choice, and use them to insert those genes into a given genome. In this case, Florence Teulé and Yun-Gen Miao used PiggyBac to shove spider silk genes into the silk-making glands of silkworms…

These engineered silkworms produced composite fibres that were mostly their own silk, with just 2 to 5 percent spider silk woven among it. This tiny fraction was enough to transform the fibres. They were stronger, more elastic, and twice as tough as normal silkworm fibres. And even though they didn’t approach the strength and elasticity of true spider silk, they were almost just as tough…

The team are also planning to refine their technique to take the silkworms’ own proteins out of the equation. “The next step will be to produce silkworms that produce silk fibres consisting entirely of spider silk proteins,” says Jarvis. Perhaps they could even use the genes from the best of the silk-producers, like Darwin’s bark spider.

Seems like a promising approach; maybe commercial products using spider silk are in our not-too-distant future. Something tells me it won’t be marketed as “spider web” though, so I’m curious to see what companies will call it when they commercialize it. 

You can read about that 11×4 ft cloth made by farming actual spiders at Wired here; the process involved capturing a million spiders off of the street in Madagascar. I previously talked about an art project mixing spider silk and human skin, where the combination was strong enough to take a hit from a bullet at reduced speed. Cool things (not human spider cool, but other kinds of cool) are in our future.

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