LOGAN -- What has four legs and can make webs as strong as a spider's?
That would be any of Utah State University's lactating "spider goats," of course.
The goats arrived with Randy Lewis, a molecular biologist who has been working more than three decades with the enzyme that allows spiders to spin strong, stretchy silk.
Lewis recently left the University of Wyoming for an endowed position at USU, where he will continue his work to produce the ultrastrong fiber and will explore ways it can be used for innovation in a variety of fields.
The stronger-than-Kevlar, stretchier -than-nylon fibers could be used in medicine to replace torn ligaments and tendons. It could be used as thread for delicate eye or nerve surgeries. Parachute pull cords or fabric could be woven from the fiber. If the right weave can be found, protective clothing could be made from the manufactured spider silk.
Lewis' research has been featured in Time Magazine and National Geographic, on PBS and on the Discovery Channel.
So where do the goats fit into all this?
"It became clear you can't farm spiders," Lewis said, recalling his early research.
"They are cannibalistic and territorial. Spiders are not like silkworms, which you can throw in a box with mulberry leaves. There was no way to collect spider silk in a commercial way."
After two years of work and experimentation, Lewis was able to clone a spider silk gene.
He has two ways of making spider silk. One involves adding it to bacteria, which grows rapidly, reproducing the silk protein. The other way is to implant the silk gene into a goat egg, or embryo, using a process developed by Nexia, a Canadian company that has since disbanded.
"They put our spider silk technology in milk," Lewis said. "The goats produce the protein only when they are lactating, then we purify the proteins from the milk, dry it down, redissolve it up and get the material we can spin into fibers."
Lewis' goats, altered with the spider silk gene, include four males, 10 kids and 20 milking females, two of which are currently lactating.
Lewis said goats were chosen over cows because goats are friendly, of manageable size and go from birth to reproducing/lactating age faster than do cattle.
The bacterial silk- producing process is good because modifications can be put into place quickly. Using goats to produce spider silk is good because a much larger quantity of the protein can be collected.
Lewis estimates that a week's worth of milk from one goat would provide the silk protein needed for fiber for one single tendon- or ligament-replacement surgery.
But such a surgery on a human subject is years away, he said. Extensive animal testing would come first.
Lewis' ongoing goal is to reproduce the strongest spider silk of the six types a spider can produce for a single web. The strongest variety is what spiders use to drop themselves from the ceiling to the floor below. They also use the strongest silk for outer circles of an orb web.
James A. MacMahon, USU dean of science, said he is excited to have Lewis on the faculty.
"We courted Randy for a while, trying to get him to join us," MacMahon said.
"As soon as he got here, he started reaching out to interact with other researchers on campus. We are trying build programs here with groups of people who can be more powerful than an individual researcher. Randy's colleagues in biology will benefit in the long run."
MacMahon said Lewis is a USTAR professor, charged with developing a commercial product that will benefit Utah's economy and potentially create jobs.
MacMahon believes the spider silk research will lead to products in the future.
"We are very excited to have Randy here."
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