Coming soon – spider socks

It is a miracle substance - lighter than feathers, stronger than steel, one of the toughest fibres found in nature. Now scientists in Japan have found a way of harnessing the remarkable power of spiders’ webs to make anything from tights and fishing nets to bulletproof vests.

Researchers at Shinshu University have succeeded in injecting spider genes into silkworms to create a thread that is stronger, softer and more durable than conventional silk. A Japanese manufacturer is already experimenting with the thread, and spider socks, stockings and even fishing lines are expected to appear on the market within a few years.

The team, based in the city of Nagano and led by Masao Nakagaki, a professor of insect genetics, has beaten rival scientists from around the world in devising a way of mass-producing spider silk.

Conventional “farming” of spiders proved impossible because of their territorial and cannibalistic nature. Five years ago American geneticists devised a bizarre means of generating spider silk by extruding it from the udders of female goats. But Professor Nakagaki’s technique employs a much more manageable creature - the silkworm, whose shimmering fibres have been used to create cloth for more than 5,000 years.

Silkworm eggs are injected with the genes of Nephila clavata, the golden orb spider, known in Japanese as the courtesan spider because its striking yellow, black and red colouring resembles the gorgeous kimono of an up-market prostitute. The silkworm caterpillars that emerge from the eggs weave cocoons, of which 10 per cent consist of spider proteins. These are spun into silk. Professor Nakagaki hopes to increase the proportion of spider thread material to 50 per cent.

“Dragline silk”, which spiders use to raise and lower themselves and to construct the spokes of their webs, has one of the highest tensile strengths of any natural substance - five times that of a thread of steel of the same thickness. In terms of its ability to absorb impact, it is superior to Kevlar, the plastic fibre used for antistab vests and body armour.

Other applications include tennis rackets and fishing line and nets - unlike nylon thread, which pollutes beaches and threatens sea birds, spider silk will degrade naturally over time. Spider thread could also be used by microsurgeons as sutures after operations. The only company developing commercial applications for the spider silk is Okamoto, a business based in Nara, central Japan, which plans to release extra-thin and durable spider socks by about 2010.

Other cultures have found uses for cobwebs. Polynesian fishermen used the threads of the golden orb spider to make fishing line and communities in Papua New Guinea put webs on their heads to keep off the sun’s rays. During the Second World War, threads from black widow spiders were used as hairs in telescopic gun sights.



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