Scientists are working on turning synthetic spider silk into high-performance athletic wear and even lightweight body armor. The black widow is known for its deadly venom, but the spider's silk may one day save lives. As this ScienCentral News video explains, harnessing its power could lead to new bulletproof vests and super strong ropes.
Toughest Silks are a Drag
Spiders make several types of silk, including wrappings for their egg cases, web silks and sticky fibers for capturing prey. The strongest type is called "dragline" silk.
Cheryl Hayashi
Spiders use it as a safety line when descending, and black widows make their entire web from it. Dragline silk is an amazing combination of strength and elasticity, pound for pound five times tougher than steel or Kevlar®. But as biologist Cheryl Hayashi explains, the problem is getting a pound of silk from the spiders.
"Spiders are predatory animals. They don't tolerate neighbors very well so you couldn't put a whole bunch of spiders in one cage. If you do that, you might end up with just a few big, fat spiders."
So for years, scientists have turned to genetic engineering as a potential way to mass-produce spider silk. In the 1990s, molecular biologists at the University of Wyoming decoded a portion of a spider silk gene. Since the genes are highly repetitive, they assumed that 10-30 percent would be enough to synthesize silk.
Proteins are difficult to construct in the laboratory, so scientists depended on other organism to make them. In 2000, Canadian firm Nexia Biotechnologies, Inc. licensed the gene-isolating technology from the University of Wyoming. They inserted the gene fragment into goats, which when mature, produced milk that contained silk proteins. The proteins can be refined from the milk and spun into thread. But using only a small portion of the gene made silk that was inferior to natural spider silk.
Nadia Ayoub
Hayashi and Nadia Ayoub are part of a team at University of California, Riverside that decoded the entire DNA sequences for two genes spiders use to produce dragline silk.
Ayoub wrote in the journal PloS One, decoding the complete sequences revealed crucial insights.
"The other end of the gene seems to have properties that are important for either making the protein or for the function of the fiber. And this should make a better fiber."
Ayoub adds, "Also there's interest in the medical field for things like microsutures. So you can make a very fine, lightweight suture that would hold together the skin, and [there would] probably be very little scarring. And there's some interest in incorporating it into things like tendons because it is both strong and stretchy."
How to Grow Body Armor
Instead of using goats to produce silk proteins, Hayashi recommends splicing the genes into crops.
"That way they could be grown very cheaply, you know, by the acre. And then the silk protein would be extracted from the plant material and this would be the way that we could get very large amounts of spider silks. We could get spider silks by the ton."
That’s enough for a whole wardrobe of spidey suits.
The researchers say it will be a few years before we can buy spider silk athletic gear and high-performance rope. The first customer for spider silk body armor, the U.S. Army, is already eager for it.
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