January 4, 2012
Super Silk From Genetically Modified Silk Worms
US researchers say they have created genetically modified (GM) silkworms that spin silk far stronger and more elastic than the normal silk produced by the critter.
Scientists from University of Wyoming, who published their research in the PNAS journal, say their ultimate goal is to produce silk from worms that has the toughness of spider silk. Spider silk, weight-for-weight, is stronger than steel. The team say the silkworm silk has a whole range of biomedical applications, including uses for bulletproof vests, sports gear and airbags for vehicles.
Researchers have been trying to produce a super-tough silk for decades, the kind like that used by superhero Spiderman, reports Pallab Ghosh for BBC News.
But it is impractical to “farm” spiders for the commercial production of silk because they do not produce enough of it. Plus, most arachnids have tendencies to eat each other.
That´s why researchers looked toward the silk worm. While their silk is typically on the fragile side unlike that of spiders, silkworms are easy to farm and they produce vast amounts of silk.
Researchers in the past have tried to transplant silk producing DNA from spiders into silkworms without much success -- generally not producing enough silk to make it worthwhile. But that has now changed.
Professor Don Jarvis of Wyoming University led the team of researchers to produce GM silkworms that seem to be producing a composite of worm and spider silk in large quantities -- and the end result so far is impressive -- the silkworm silk is as strong as spider silk.
Dr Christopher Holland from the University of Oxford told Ghosh that the development represented a step toward being able to produce toughened silk commercially. “Essentially, what this paper has shown is that they are able to take a component of spider silk and make a silkworm spin it into a fiber alongside its own silk,” said Holland, who was not involved in the study.
The researchers also managed to show that this composite, which contains bits of spider silk and mainly silkworm silk, has “improved mechanical properties,” he added.
“This research represents a significant breakthrough in the development of superior silk fibers for both medical and non-medical applications,” Malcolm J Fraser, a Notre Dame University professor of biological sciences, told Kate Taylor of TG Daily. “The generation of silk fibers having the properties of spider silks has been one of the important goals in materials science.”
“Several years ago, we discovered that the piggyBac transposon could be useful for genetic engineering of the silkworm, and the possibilities for using this commercial protein production platform began to become apparent,” he said.
“Using this entirely unique approach, we have confirmed that transgenic silkworms can be a potentially viable commercial platform for production of genetically engineered silk proteins having customizable properties of strength and elasticity. We may even be able to genetically engineer fibers that exceed the remarkable properties of native spider silk,” said Fraser.
While the silk could be used in a wide array of applications, including those in the medical and the environmental sector, there are concerns about creating GM silkworms for industrial applications. The main concern being if they escaped into the wild.
But according to Professor Guy Poppy of Southampton University, they would not pose an environmental threat and he believes the benefits would outweigh any risk. “It´s hard to see how a silkworm producing spider silk would have any advantage in nature,” he told BBC News.
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