Biologists have inserted spider genes into silkworms, allowing them to produce strong, elastic threads that may be used to make sutures and wound-healing bandages as well as bulletproof vests and lightweight fabrics, researchers said Wednesday.
Malcolm Fraser Jr., a University of Notre Dame professor of biological sciences, called the development significant because it could allow for widespread production of spider silk-like thread, something scientists have long pursued because it is strong and flexible and has many uses.
"It's very difficult to get spiders to make a whole lot of silk. They usually don't make very large quantities," Fraser said at a news conference at Notre Dame. "For the first time it's possible to make spider silk commercially usable."
Gregory Holland, an assistant research professor in chemistry at Arizona State University who has studied spider silk fibers, agrees incorporating spider silk into silkworm silk is significant. But Holland, who in the past collaborated with one of the researchers involved, said in a telephone interview that it's difficult to gauge the ultimate applications until the work undergoes the peer review process and is published in a scientific journal.
"What do the mechanical testings look like? The press release says it's approaching spider silk (strength). How close is it?" Holland asked. "If they're producing something that's stronger than silkworm strength but is still five times less strong than spider silk, then it's not nearly as big of an accomplishment."
Fraser said he is confident the work he did along with biochemist Randy Lewis and molecular geneticist Don Jarvis, both at the University of Wyoming, and Kraig Biocraft Laboratories Inc. of Lansing, Mich., will stand up to scrutiny. He said the group didn't release too many specifics because some final work has to be completed before submitting it to a journal.
"I'm sure there are people who will try to poke holes in what we've done, but there are no holes," he said.
Fraser said scientists around the world have been trying to develop an artificial spider silk through a variety of genetically engineered biological systems for more than a decade, including transgenic goats, bacteria and plants. Until now, though, scientists had been unable to come up with a commercially viable way for spinning the silk proteins into a fiber.
He said the new process allows them to create different protein fibers in the silk. The spider silk may be used to make compounds that might be used in sutures and bandages to stimulate the growth of normal tissue instead of scar tissue for burn victims or plastic surgery, Fraser said.
"Then you wouldn't have such stiff and thick healing at the site," he said.
The artificial spider silk also could be used as scaffolding material to grow stem cells for generating bone, cartilage, ligament and tendons, Fraser said.
And it may be an option for replacing Kevlar in making bulletproof vests. Fraser said the spider silk is better because it is more flexible. Holland said spider silk also is more environmentally friendly because harsh chemicals and solvents are used to make Kevlar.
"Obviously the insect makes it from protein and water, which is completely environmentally friendly," he said.
Fraser said the genetically altered silkworms breed and the offspring still produce the thread with the spider silk.
"So basically that's going to be carried on from generation to generation," he said.