From spiders, a material to rival Kevlar
FORTUNE — A Japanese startup claims it has cracked the knotty problem of commercializing the production of spider thread, which, gram for gram, is stronger than nylon and even many metals. As one of nature’s super-substances — tougher than Kevlar yet significantly more elastic — scientists have been trying to recreate it in significant quantities in labs but failed for over a decade.
By using synthetic biology techniques and a new spinning technology, Spiber Inc. says it is now able to produce many hundreds of grams of synthetic spider silk protein where past efforts have produced less than a few grams over a day. One gram of the special protein produces about 9,000 meters (29,527 feet) of silk.
The breakthrough, says the inventor and Spiber’s president, Kazuhide Sekiyama, is that unlike other attempts to synthesize spider thread the Japanese researchers did not try to copy the spider’s little-understood spinning action. Using duct-like spinnerets, spiders rearrange a simple protein to turn it into silk. “We make fibers using a totally artificial process,” he told Fortune.
In the world of biomimicry, or biomimetics, where cutting edge analytical techniques are helping put some of nature’s better ideas to work in industry, spider silk is something of a holy grail.
Engineers have been adept up to now at synthesizing a range of extremely useful materials. But they could do better. Kevlar, for example, is a remarkably strong fiber used in aeronautics and bullet-proof vests. Made by heating petroleum products to 1,400 degrees Fahrenheit, then applying substantial pressure, the fiber is teased out to make the final fabric.
To a spider, the process would seem a tad hyperactive. Without using anything like that kind of heat, spiders produce a material that’s many times stronger than Kevlar, not to mention biodegradable. Clearly, a synthetic equivalent of spider thread would be of enormous benefit. Biomimetics and synthetic biology helps scientists create spider thread not by copying it exactly but by incorporating some of nature’s design aspects. It also shows the potential of such synthetic biology — breaking down nature into spare parts and then rebuilding them back up as desired.
This can take inventors down some strange avenues. Ten years ago, U.S. researchers came up with the idea of creating “Spider goats” that had their milk genes altered with spider DNA. The resultant animal’s milk contained the spider silk protein which was then extracted following milking. After that the task got harder.
So far, what has held scientists back, says Michelle Oyen, professor of Mechanics of Biological Materials at the University of Cambridge, is understanding the natural materials well enough to mimic them. “In the case of spider silk, we can copy the gene sequences responsible for silk and transfer them elsewhere, as with the goat’s milk case,” she says. “But we then have to mimic the spider’s silk spinneret in order to form the proteins into fibers, and that’s tricky and has been one of the limitations to date.”
Spiber, capitalized at 780 million yen, is now capable of producing up to 1 kg of the silk protein a day and is confident enough to form a joint venture with a Toyota (TM) subsidiary to commercialize production. The yarn proteins at Spiber are made by synthetic microorganisms — not goat’s milk. Spiber is currently building a test plant that will produce 100 kg a month of patented spider thread protein, dubbed Qmonos Fiber, by the end of the year. A pilot plant will then be built for commercialization of the yarn by 2015 that will produce over 10 tons silk annually.
“Applications will include super-light but strong car parts and medical applications,” says Sekiyama. “We have an idea for cars that won’t hurt pedestrians in crashes.” Spider silk’s tensile strength but corresponding flexibility could make it ideal for artificial ligaments. One claim, however, that Prof. Oyen wishes to disabuse us of, is that spider silk is stronger than steel. “At best, spider silk might compare to steel when it comes to tensile strength. Tensile strength is only one critical property,” she says. “The stiffness of silk, which is its ability to deform elastically when force is applied, is many times less than that of steel.”
Nevertheless, Spiber is not alone in the race to market such a potentially valuable substance. German firm Amsilk recently announced it, too, will start a pilot project to scale up lab production of spider silk. Meanwhile, the American company that originally created the spider goats, after securing millions of dollars in backing, is no longer in the spider web business. The goats, now a Utah university farm, still produce spider proteins. But for the time being, the protein-synthesizing micocrobes seem to have the lead.