Randy Lewis arrived at Utah State University a month ago, bringing with him a long history of research into spider webs that may lead to durable artificial ligaments for people who have injured knees or shoulders. “I have been studying spider silk and their proteins for about 20 years,” said Lewis, a new USTAR professor. Lewis has been published in some of the nation’s most prestigious scientific journals and has appeared several times on the Discovery Channel. He said silk fibers have very different mechanical properties. How to synthetically develop these silks is one focus of Lewis’ research. “Unfortunately spiders tend to be both territorial and cannibalistic so you just can’t farm them. Their webs are made out of different kinds of silk. The spiders we’re interested in, called orb-weavers, make four different silks with very different properties. Some tend to be very elastic and not very strong while others tend to be strong and not very elastic. “What we’ve done is teased out the information for each of those different kinds of silks and have designed a system to make them, if you will, artificially.” Lewis said the research has progressed to the point that the spider silk proteins are being produced in bacteria. “That’s pretty standard, but it is difficult to scale it up. It’s fast and relatively cheap at small scale but at large scale it becomes prohibitively expensive.” He said the secret to producing large quantities of spider silk is to use “factories” designed to manufacture proteins that are easily scale-able and efficient. Lewis’ factory of choice is through genetically modified goats and also transgenic alfalfa. “Also, in collaboration with a company here in Logan we’re trying to put it into cottonseeds,” said Lewis, “because cottonseeds are basically waste to cotton farmers and we hope that will be another large scale but relatively cheap way to produce spider silk proteins.” Lewis said the silk he is most interested in makes the outside framework of the web and the little spokes seen in webs. He said it is stronger than Kevlar and more elastic than nylon. “And that is why we’re interested in using it for things like ligaments and tendons because it’s very strong, it’s biological. Preliminary studies indicate that when you implant it in animals you don’t get an immune response or an inflammatory response. “It has many of the properties people like in silkworm silk, yet it’s much stronger and more flexible.” He said there has been a lot of interest to use the technology in applications to make new kinds of airbags, to use in athletic shoes, for protective clothing like bullet proof vests, parachutes and parachute chords and in new fabrics with the same feel as silk with the same “…kind of silver sheen as silk fibers have.”
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