It worked for Peter Parker: Genetic scientists unleash power of the
spider web
Breakthrough may pave way for new
biomaterials that could be used in medicine and engineering
by Steve Connor
Scientists have created genetically-modified silkworms that can spin
the much stronger silken threads of spiders in a technological
breakthrough that promises to revolutionise the production and use of
new materials made with spider silk.
For more than a quarter of a century scientists have been trying to
find ways of producing industrial-scale quantities of spider silk
because, weight for weight, it is stronger than steel and almost as
tough as bulletproof Kevlar. A net weaved from pencil-thick rope spun
from spider silk, for instance, could in theory catch a fighter jet in
flight without breaking.
However, unlike the caterpillars of the silk moth Bombyx mori,
spiders are territorial, aggressive and prone to cannibalism, making it
impossible to rear them in the population densities required for
commercial silk production. Researchers have attempted to overcome this
difficulty by transferring into silkworms the key spider genes
responsible for making the silk threads used in the draglines of the
golden orb-web spider.
The result was a genetically-modified "transgenic" silkworm that
produced a mixture of its own silk combined with the far tougher and
stronger threads of spider silk within the mile-long threads of its
cocoon.
The researchers, led by Professor Don Jarvis of the University of
Wyoming, in Laramie, published their study in the journal Proceedings of
the National Academy of Sciences, showing how they created transgenic
silkworms capable of making composite fibres with silk threads from both
spiders and commercial silkworms.
"On average, the composite fibres produced by our transgenic silkworm
lines were significantly tougher than those produced by the parental
animals and as tough as native dragline spider silk fibre. In best-case
measurements, the composite fibre produced by one of our transgenic
silkworms was even tougher than the native dragline spider silk fibre,"
the scientists said.
Some possible uses for spider silk have already been identified in
medicine, such as new kinds of biomaterials for wound dressings,
artificial ligaments, tendons, tissue scaffolds and microcapsules for
drug delivery, they say. Other uses could include materials used in
bulletproof jackets and engineering.
Ever since scientists first identified the spider genes involved with
silk production, biotechnologists have tried to created
genetically-modified alternatives to spiders. Synthetic spider silk
genes have been transferred into bacteria, tobacco plants and even
goats, which produced limited quantities of silk proteins in their milk.
However, none of the transgenic microbes, plants or animals carrying
spider silk genes have been able to produce sufficient quantities of the
pure proteins needed for commercial-scale production.
But it is hoped that the Bombyx mori silkworm, which has a proven
record in industrial silk production, may finally offer a solution to
the scale-up problem.
- The Independent
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