By Elizabeth Howell
Ultra-strong spider silk, one of the toughest known natural fibers, could one day protect soldiers on the battlefield from bullets and other threats, one company says.
Spider silk is light and flexible, and is stronger by weight than high-grade steel. Its potential applications span a wide range of industries, from surgical sutures for doctors to protective wear for the military. But producing and harvesting enough spider silk to make these types of products commercially available has posed a challenge.
Kraig Biocraft Laboratories, based in Lansing, Michigan, genetically engineered silkworms to produce spider silk, and has used the material to create gloves that will soon undergo strength testing.
“Spider silk in nature has truly unique properties. If you think about a spider’s web, it’s designed by nature to intercept an airborne missile — a fly or another flying insect,” Kim Thompson, CEO of Kraig Biocraft Laboratories, told Live Science.
The silk naturally elongates and absorbs the energy of the captured prey, he added. “If you do the mathematical calculations — the weight of the fly, its speed, and the size of the individual fiber you capture it in — the strength-to-weight ratio is off the scale,” Thompson said.
For soldiers in particular, spider silk could provide a new type of protection beyond than the traditional, solid Kevlar vest.
Thompson has been working on this idea for about 10 years, since he watched other companies try, and fail, to make silk a viable material for armor.
He said that past projects, including one that used goat milk to enhance the spider silk, lacked a key ingredient: repeatability. By contrast, if one silkworm could be genetically engineered to make spider silk, its descendants could carry on that trait forever, Thompson said. Unlike spiders, silkworms are able to assemble silk proteins that are already being used for mass production of silk fiber for clothing.
In 2011, scientists who are part of the Kraig advisory board published a paper in the Proceedings of the National Academy of Sciences about genetically engineered silkworms that spin a type of composite spider silk.