A team of scientists from a Canadian biotech company and the U.S. Army has finally solved the mystery of how to make spider silk, a 400-million-year-old product stronger than steel and tougher than a bulletproof vest.
The team extracted silk-making genes from two orb-weaving spiders and implanted them in cells from a cow's udder and a hamster's kidney. The cultured cells secreted a water-soluble protein "soup" that was squeezed through a syringe-like aperture, creating a crystalline silk filament like the fiber a spider uses to rappel from the ceiling or to make the spokes of its web.
Details of the research, developed by Montreal-based Nexia Biotechnologies Inc. and the U.S. Army Soldier and Biological Chemical Command, were published in last week's issue of the journal Science.
"The principle of biomimicry works," said geneticist Jeffrey Turner, president and chief executive of Nexia, referring to the development of new technology using models and designs drawn from nature.
Turner explained that spider silk -- developed through 400 million years of evolution -- is at least five times stronger by weight than steel, with remarkable toughness and elasticity, a combination of properties unmatched by any known synthetic fiber. The ability to make spider's silk has been what Turner called a "Holy Grail" of material science for years.
Turner said Nexia's goal is to strengthen the man-made silk enough so it can be used to make soft body armor. It is already strong enough to be made into soluble sutures for delicate surgery or as biodegradable fishing line.
To produce the protein in large enough batches, the team has implanted the gene in the eggs of nanny goats so female offspring will secrete the protein in their udders. "All we'll have to do is milk the goats," Turner said.