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Genetically Engineered Silkworms Spin Like Spiders

If Spider-Man ever ran out of webs, he could now enlist an army of silkworms to spin extra high-tensile spider silk.
/ Source: Discovery Channel

If Spider-Man ever ran out of webs, he could now enlist an army of silkworms to spin extra high-tensile spider silk.

Scientists have created a genetically modified silkworm that spins a new kind of silk: a hybrid of silkworm silk and spider silk.

The new material alone could shake up the textile industry, while future silk hybrids could be used in everything from bulletproof clothing to artificial tendons.

"Compared to normal spider silk, it's not as strong," said Malcolm Fraser, a scientist from the University of Notre Dame. "But we are confident that, this being our first attempt, that we will be able to tweak the system to bring the system closer to the strength of true spider silk."

Fraser, along with professor Randy Lewis from the University of Wyoming, developed the spider-silk-spinning silkworms.

Silkworms have helped clothe people for thousands of years by reliably producing large quantities of a soft, supple and luxurious material.

Spider dragline silk is significantly stronger than silkworm silk -- so strong that it can best steel wire -- but it is hard to make.

"They just don't produce enough silk," said Fraser, who notes that a golden cloth on display at the American Museum of Natural History in New York City required more than one million spiders to produce. "One million silkworms can produce considerably more silk than one million spiders."

The new silk is a hybrid of spider silk and silkworm silk. It is stronger and finer than silkworm silk, but not quite as strong as spider silk. "It would definitely be stronger (than a normal silk shirt)," said Lewis. "But it wouldn't flow like silkworm silk does."

"It's a fabulous accomplishment," said Cheryl Hayashi, a spider silk expert and a professor at the University of California, Riverside.

Other groups have produced spider silk protein in plants, in bacteria and even in goat's milk. But spider silk protein is not the same as spun spider silk. The silkworms have the necessary body parts to spin the protein into silk threads -- and to produce it in large quantities.

The new silk alone could shake up the textile industry by creating a softer, stronger fabric that still looks like silk.

Fraser and his team, however, have bigger plans in mind.

In this work the Notre Dame and University of Wyoming scientists replaced only one of multiple silk-producing genes in silkworms with spider silk genes. Eventually they want to replace multiple silkworm silk-producing genes with spider silk genes.

In particular, they hope to insert genes from the newly discovered Darwin's Bark Spider (Caerostris darwini), which produced silk twice as strong as any other. That's more than 10 times stronger than Kevlar, a fabric commonly found in bulletproof vests.

Mass produced, stronger-than-steel spider silk will also have a range of biomedical applications, said Fraser and Lewis. Hybrid silk could be speed wound-healing, eliminate or reduce the need for cadaver-derived tendons and ligaments.