ST. GEORGE — It sounds like something out of science fiction: synthetic spider silk used to create fabrics, body parts and equipment. Yet that is exactly what researchers in northern Utah are trying to create in the real world. The U.S. Army recently contracted with Utah State University and Technology Holdings LLC to begin creating synthetic spider silk.
Dr. Randy Lewis, Utah Science Technology and Research professor of biology at Utah State University is in charge of the program.
Lewis has spent a quarter century studying the properties of spider silk and, with his colleagues at the University of Wyoming and now at Utah State University, has created some unique methods for creating its synthetic cousin. Utilizing bacteria, goats and silkworms to create the proteins necessary to synthesize the material, Lewis is hopeful that by the end of March 2016, spider silk can be made in larger quantities than is possible today.
“Our plan is that we expect to be able to produce in the first quarter of 2016 … about a kilogram, or 2.2 pounds of spider silk protein per week,” Lewis said. “That’s enough material to make about a hundred-thousand yards of thread.”
Researchers at USU are studying the web properties of the Golden Orb Weaver spider.
Spider silk, unlike silkworm silk, cannot be farmed. Spiders have too many personality defects, Lewis said.
“They have a couple of psychological problems,” Lewis said. “One, they’re territorial and two, they’re cannibalistic.”
Additionally, natural spider silk is composed of several different varieties of silk, all of which have different mechanical properties, and extracting the different varieties organically is impossible, Lewis said. Combining the different types of silk creates a material that loses all the unique qualities the different varieties possess.
“The silk that most people are interested in is called dragline. It makes the framework of the web and the radii. It has the tensile strength about the same as Kevlar, one of the strongest man-made materials,” Lewis said. “But … Kevlar doesn’t stretch at all. The dragline itself will stretch 20-30 percent. As a result, it absorbs much more energy than Kevlar.”
Besides dragline, the other types of silk allow for a wider variety of applications, Lewis said. Artificial ligaments and tendons, extremely fine sutures, blast resistant materials, clothing, cordage and even sporting goods are all possible uses for synthetic spider silk.
“In particular, the funding we have gotten from the army for the next two years is to try to develop, in essence, a material that will replace nylon,” Lewis said. “The major reason for that is they’re looking for something that won’t melt when it gets hot.”
Nylon melts when it reaches high temperatures, often causing burn injuries on soldiers, even when an explosion does not directly impact the soldier, Lewis said. Spider silk, however, breaks down and becomes charred when it gets hot. Uniforms made of silk would not melt onto the skin of soldiers in those circumstances.
The spider silk project is a joint effort between Lewis and the University of Utah and Technology Holdings of Salt Lake City.
“Their (Technology Holdings) goal is to commercialize it and ours is to help them produce enough silk and develop the prototypes that we can send to the army for testing,” Lewis said. “They have expertise in getting bacteria to make various kinds of products in large quantities. That obviously is one of the things we need to do — we need to get the bacteria to make lots of spider silk protein for us.”
There are three different ways of making spider silk protein, Lewis said. One is by using transgenic (being or used to produce an organism or cell of one species into which one or more genes of another species have been incorporated, according to the Merriam-Webster online dictionary) bacteria, transgenic goat milk or transgenic silkworms.
The silkworm-spider combination has a lot of potential, but ultimately has limitations because there is no way to change what the silkworm produces, Lewis said. The bacteria, on the other hand, allows researchers to produce different proteins more easily. Additionally, the bacterial silk proteins can be spun into different fibers to allow for a wider variety of properties — some stronger or some more elastic — something that cannot be done with the silkworms.
The goats produce the silk proteins in their milk, but Lewis said that they are the least hopeful option of the three, due to the limitations in milk production. While the goat milk is the most straightforward method for producing the proteins necessary, it is also the most costly and time-consuming.
Control elements are added to each of the different organisms combined with the spider silk gene, Lewis said. With the goats, the gene is combined so that the proteins are only created when the goats are lactating. With the silkworms, that control element is such that the gene becomes active as they are about to make their cocoons, and with the bacteria, the gene is not activated until the bacteria has a high density, since they will not grow very well once the proteins begin producing.
For the moment, researchers are focusing more on making the process as efficient and inexpensive as possible, Lewis said. There is no point in ramping up production until the process itself is better understood.
A small army of teachers and students are working on this project, Lewis said.
“We have one senior scientist. We have five post-doctoral fellows, eight graduate students and then we have something on the order of 26-30 undergraduate students who work in the lab anywhere from a few hours a week to basically half-time when their studies allow them to do it,” Lewis said.
The hope is, Lewis said, that once the process is firmly established, Utah will be at the forefront of the burgeoning industry.
“That’s part of the reason we partnered with Technology Holdings,” Lewis said. “We have a local company that has both the interest and the capacity to move forward the commercialization with us. That’s really why we chose to do it. The expectation is that at the end of two years, when we talk to the army about a contract to produce the material for them, that will be where Technology Holdings or a joint spin-out between themselves and us … here in Utah we’ll start getting production.”
Lewis, the University of Utah and Technology Holdings are not alone in their efforts to produce and fabricate synthetic spider silk. According to a report in Wired magazine, startup company Bolt Threads, based in Emeryville, California, claims to have created a process utilizing yeast fermentation to mass produce synthetic spider silk. A Japanese company called Spiber has also been synthesizing spider silk, and in partnership with outdoor clothing giant The North Face, has created a parka made from this material, according to a report by PSFK.com.
Spider silk also “appears to be a promising biomaterial for the enhancement of skin regeneration,” according to a report published in the Public Library of Science.
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