The US Army has given a company a contract, potentially valued up to $1 million, to develop a material code-named “Dragon Silk.” No, it isn’t actually trying to replicate the mythical qualities of the scales of Drogon from Game of Thrones. However, it is possibly the far superior successor to Kevlar, the bulletproof, life-saving material worn by combatants the world over – and it is made from spider silk, one of the strongest natural fibers known to science.
Kraig Biocraft, the bioengineering company in question, has for some time been using genetically altered (transgenic) silkworms to produce a special form of spider silk. Although spiders themselves normally produce this, making a cost-effective spider silk farm is notoriously difficult. After all, they don’t continuously produce silk, and certainly not enough to be harvested. Their cannibalistic behavior also tends to be something of a problem.
On the other hand, their transgenic silkworms have been producing a composite silk – as strong as spider silk but far easier to produce – for some time now, which has now been dubbed “Dragon Silk.”
Thanks to its basis in spider silk, bundles of this material are quite resistant to friction and impacts. It should come as no surprise, then, that the US Army has asked Kraig Biocraft to produce several ballistic “shoot packs” in order to see if they’d make effective body armor.
The main advantage of this material over Kevlar is that it’s far more flexible and at least 10 times as elastic. Kevlar is essentially inflexible, whereas Dragon Silk could be wrapped around a variety of complex shapes.
The downside is that Kevlar is still “stronger” overall, in that it can withstand forces of up to 3 gigapascals (435,113 pounds per square inch) as opposed to Dragon Silk’s 2 gigapascals (290,075 pounds per square inch). Still, this is pretty good going – the maximum pressure exerted by a .44 magnum shell is 0.25 gigapascals (36,000 pounds per square inch).
Image in text: Silkworm larvae, which eventually become moths, have been genetically altered to make spider silk. Fastily/Wikimedia Commons; CC BY-SA 3.0
Compared to other companies attempting to produce spider silk technologies, the use of transgenic silkworms is proving to be remarkably cost-effective. A rival, AMSilk, produces their equivalent of Dragon Silk at a cost of $137,500 per kilogram, whereas Kraig Biocraft manufactures it for just under $300 per kilogram. They also claim to be the only spider silk material manufacturers that have peer-reviewed publications to their name.
If the contract goes well, it may no longer be Kevlar but genetically engineered spider silk, that protects soldiers and military personnel around the world from potentially fatal injuries. It now appears that they are in competition with the US Air Force, who is banking on taking advantage of the tough plating of the psychopathic mantis shrimp to design some advanced armor once again inspired by nature.
