Materials scientists have been eyeing spider silk as a potential supermaterial for years, but the stuff is notoriously difficult to produce in quantities. Now, recent breakthroughs in the production of synthetic spider silk could see this remarkable substance commercialized, and publicly available, sooner than expected.
Image Credit: AMSilk via C&EN
Spider silk is amazing stuff. Five times stronger than steel and three times stronger than Kevlar, by weight, and with near-unmatched heat-conducting properties, spider silk has potential applications in everything from bullet proof vests to computer electronics. But producing and collecting it is damn challenging. As Chemical & Engineering News' Alex Scott explains:
...gathering the silk from farm-raised spiders, which are territorial and cannibalistic, is not an option. Firms attempting to make spider silk synthetically have copied relevant genes from spiders and inserted them into organisms, such as Escherichia coli, that can express the protein. The protein, though, is complex, and producing silk that is as strong as nature's has proven elusive.
Further challenges faced by would-be producers are that the protein is insoluble in water and the fiber is so fine—1,500 strands are needed to make a thread—that firms have had to invent new spinning systems. After years of trying to develop commercial spider silk, big companies including DuPont and BASF have dropped out, with the latter pulling the plug on its research just last year.
But where corporate giants like DuPont and BASF have failed, AMSilk – a venture-capital-backed German firm currently comprising just 25 staffers, 22 of whom are scientists – appears to have met with success. The company's process uses genetically engineered E. coli samples to express silk protein derived from the DNA of the European garden cross spider, and is capable of generating about 20 different silk grades from four silk varieties. Over the last few months, AMSilk has been selling their E. coli-grown spider silk protein to shampoo and cosmetic companies for incorporation into their products. In the materials industry, these are known as nonfiber applications; in other words, the silk is being used to give skin and hair a silky smooth feel, not make your shampoo impervious to bullets, or your hair as strong as steel cabling. What it is, however, is a sign that it is, in fact, possible to produce spider silk protein at reasonable enough cost to see it marketed – and across an impressive range of applications. Via C&EN:
The company is already outsourcing production and says it can increase output as required. "This is scalable technology," Managing Director Axel H. Leimer says. "If someone ordered 1 ton, we could make it. We have already made a half a ton," he says. For the first time, a company is producing recombinant spider silk that is as tough and strong as the silk from a spider, Leimer claims.
Leimer is hoping that AMSilk's know-how will enable it to roll out products generating annual sales in the next couple of years of more than $10 million. He is targeting sales of more than $100 million once large-scale production of synthetic fibers is under way.
Leimer hopes that, by the end of 2015, AMSilk's spider silk protein will also be on the market as a dip coating for silicone breast implants. The protein changes the properties of the implant, making its hydrophobic surface slightly negatively charged and reducing the body's reaction to it, Leimer says. "It's a double-digit million-dollar market for spider silk."
As for large scale output for fiber-products and high performance textiles, Leimer says it'll come after 2015.
For much, much more on this, check out Scott's in-depth piece over at C&EN.