San Francisco startup spins laboratory-grown silk

San Francisco

FIVE years ago, the graduate students behind a secretive startup called Bolt Threads set out to replicate the unique chemical properties of spider silk, an almost magically flexible and durable material that's in some ways as strong as steel. One of the first things they did was buy a batch of Nephila spiders - the common golden silk orb-weavers - from an insect dealer in Florida. Then they let the spiders spin their webs all over the company's first office at the University of California at San Francisco. One day a well-known UCSF molecular biologist walked in, saw a spider hanging in a doorway, and ran away screaming.

Scientists, at least those who aren't arachnophobes, have tried to mass-produce spider silk for decades with little success. Spiders are territorial and cannibalistic - try to farm them, and they end up eating each other. But scientists have long believed that if spiders would only cooperate, fabric made from their silk would be well-suited for use in military and medical equipment, like wound sutures or artificial tendons, as well …