A soft, thin yet strong material is garnering attention worldwide as something of a dream in the 21st century: spider silk.
Shigeyoshi Osaki, a specially assigned professor at Nara Medical University, says spider silk “has a 400 million year-long history in evolution. It is mystic and has profound implications.”
Osaki, 67, has studied spider silk for more than 35 years. He even produced a set of violin strings made of about 15,000 strands of natural spider silk.
The professor once wrote in a respected science journal that, unlike ordinary violin strings, those made of spider silk can produce richer sounds with more depth – much to the surprise of professional musicians.
Mass-producing spider silk strings is a challenge because spiders tend to eat each other if they are kept together.
A team of researchers led by Yohsihiko Kuwana, a senior researcher at the National Institute of Agrobiological Sciences based in Tsukuba, Ibaraki Prefecture, found a way around this problem by implanting certain spider genes into the genes of silkworms.
Spider-infused silk produced by the genetically modified silkworms contains a protein that forms spider silk. Even though the protein accounts for only 0.4 per cent to 0.6 per cent of total weight, the researchers say the genetically modified silk is 1.5 times stronger than ordinary silk.
“Silkworms can be bred in large numbers,” says Kuwana. “Spider-infused silk fibers can also be machine-processed for production.”
There are theories the silk strength could be boosted further if the percentage of spider protein is raised. If realised, the researchers say, the new material will have a wide variety of applications including clothing and surgical suture threads.
Spiber Inc., a start-up company based in Tsuruoka, Yamagata Prefecture, which came about from a project at Keio University, aims to use microbes to mass-produce proteins that form spider silk.
Implanting genes into microbes so they produce various kinds of proteins is easily done. The project’s success could give way to order-made spider silk threads with custom levels of strength and colors.
The company is currently searching for the best genetic sequence to implant into microbes.
“We hope to release our products made of spider silk fibers onto the market within several years,” says Kazuhide Sekiyama, 31, representative executive officer of Spiber, who established the company in 2007.