Who uses spider silk? The Army and Stella McCartney, for starters

Sep 15, 2017

You know the story: Boy meets spider. Spider bites boy. Boy develops extraordinary powers – and uses spider silk to design uber-cool suit.  

Now, scientists are flirting with the world of sci-fi – and using genetic engineering to develop real-life uses for that silk.


These silk threads are mass produced by silkworms but based on the protein a spider uses to spin its web.
Credit Kraig Biocraft Laboratories

The U.S. Army recently inked a more than $1 million deal with Kraig Biocraft Laboratories. The Michigan company is developing an elastic yet durable fiber that can be woven into protective clothing.  

The science is fairly new.  But the source is very old.

"Silkworms produce silk.  Spiders produce silk.  They have different recipes; different designs," says Kraig Labs Chief Operating Officer John Rice. He's describing the protein silkworms use to spin their cocoons and spiders their webs.

Spiders produce a particularly tough material. Problem is, it’s hard to round up a lot of spiders in one place to harvest their silk. They tend to eat each other.  

So Kraig Labs had to get creative.

"We’ve taken that recipe from the spider, re-created that and created an enhanced silkworm; a genetically engineered silkworm that produces that spider’s design," Rice said.

Jon Rice
Credit Kraig Biocraft Laboratories

In essence, company scientists taught a silkworm how to act like a spider.

Spider silk is more elastic than Kevlar, the fibrous material found in the Army’s combat helmet since the 1980’s.  Rice says his company’s product could also be used in body armor and even protective undergarments.

Other researchers are using spider silk for sutures, bandages and optical fibers.

And not far away, another group of scientists is working on synthetic silk.  

At Michigan State University’s Bioeconomy Institute, business development manager Chad Pastor shows a visitor a frothy liquid that's churning in a cylinder about the size of an espresso maker. Inside is replicated spider DNA.

But there are no spiders in sight. 

"They don’t exist," Pastor says. "The real stars of the show are the microbes that are making the products themselves." 

Operations Coordinator Briana Marlatt monitors a mixture that includes yeast and spider silk proteins at the Bioeconomy Institute in East Lansing, Mich.
Credit Kevin Lavery, WKAR

Pastor says yeast is mixed with genetic material in a fermentation chamber to make microbes that will eventually grow ... and grow ... and grow.

" So the same way you’d brew beer is the same way that they make these proteins," he says. "And then you separate the proteins, purify them; then they extrude them and they spin them into threads to make fabrics."

Eventually , a dense liquid is shipped to California-based Bolt Threads, to be woven into fiber.  

Bolt Threads is collaborating with a British designer who knows something about spiders.

And Beatles.

Yep, Sir Paul’s daughter, Stella McCartney. She’s designed a brilliant gold dress made from synthetic spider silk yarn.

Chad Pastor
Credit Bioeconomy Institute

Silk protein fabrication is still a developing science. But Rice of Kraig Labs says his company is leaning on experience the textile industry has built over centuries.

"We have 4,000 years of history, of process, of equipment, of manufacturing, of design, of labor that all know how to do this very, very well," he says.

And here’s the bottom line.  With the advent of gene sequencing, the cost of replicating spider DNA has dropped dramatically. Rice says that’s clearing the way for more products to come to market.

That’s all there is to tell for now. This yarn has been spun.