Silkworms Will Mass-Produce Spider Silk Because Spiders Won’t

One company is working with the established silk industry in Vietnam to mass-produce the new material.

Jun 18 2015, 11:50am

Transgenic silk moths. Image: Kraig Biocraft Laboratories

Spider silk is something of a natural supermaterial. It's strong, light, flexible, and biodegradable. But spiders don't make much of the stuff, so in recent years scientists have found various ways to fake it. The next step to seeing this super silk in wider use is mass production.

This week, Michigan-based Kraig Biocraft Laboratories, which makes "spider" silk using transgenic silkworms, announced it had signed a "emorandum of understanding" with the provincial government of Vietnam. It pairs a new technology in the industry—genetically engineered silkworms—with one of the major silk producing countries in the world.

"The sericulture industry in that part of the world has existed for thousands of years," said Jon Rice, chief operations officer at Kraig Labs. "So what we've done is we've taken this really well-defined manufacturing system that they have in place and we're saying, how can we leverage that to produce more powerful material?"

Sericulture is a name for silk farming—rearing silkworms to make silk. Kraig Labs tweaks the process from the beginning by genetically modifying the worms so that they simply produce a modified silk. The company boasts around 20 different silk fibers based on different genetic sequences.

Silkworms on mulberry leaves. Image: Kraig Biocraft Laboratories

Getting silk from silkworms is a relatively simple process, which follows the natural life cycle of the silk moth (silkworms are actually caterpillars). Rearing the silkworms starts with hatching the eggs laid by moths and raising the larvae on mulberry leaves. When they're old enough they'll wrap themselves up in a cocoon, a continuous fibre of raw silk. The cocoons are harvested (a process that, sadly, usually means killing the pupae) and the strands twisted together to create a thread of the desired diameter.

"The absolutely beautiful part of what we're trying to do is we're doing nothing different," said Rice, noting that silkworms are reared just like this in Vietnam already. "We've just tweaked—just slightly modified—the starting point, so that what comes out at the end of the process is completely different, but the process itself is exactly the same."

That "tweak" builds on research at the University of Wyoming to genetically modify the silkworm to produce silk containing proteins found in spider silk. So the silkworm does its thing as usual, but produces silk with those super spidery qualities.

Rice shared a cool fact: Note the red eyes on the silk moth in the image above—silk moths don't usually have those. The team adds a marker to their modified silkworms so that they can identify those that are transgenic. If they are, their eyes glow red.

A tray of cocoons. Image: Kraig Biocraft Laboratories

There are other ways of producing faux spider silk. Just last month MIT researchers published a paper explaining how they'd made a material with the properties of spider silk using genetically modified bacteria in the lab, and other research groups have succeeded with similar synthetic methods. One company, Bolt Threads, is even starting to make clothes with lab-made silk.

But Rice thinks harnessing the existing powers of the silkworm is the way to go. "Nature has spent millennia optimising the performance of the silkworm," he said. If you're wondering why they don't just rear spiders, they're simply not very open to domestication. They like eating each other, for one.

The potential end uses for spider silk products are varied, though we've only seen a few samples here and there. Kraig Labs' silk has been used in a pair of gloves, and a Japanese company called Spiber claims to have made a cocktail dress out of artificial spider silk. But beyond fashion, one major potential application could be in medical implants, as the material is biocompatible.

Following the memorandum of understanding with Vietnam—a result of talks with central and regional government—Kraig Labs hopes to continue to develop their technologies and step up production capacity while leveraging the expertise of the more conventional sericulture industry.

With many laboratories and companies talking about mass production, we're a step closer to seeing spider silk, or a version of it, in real-world products.