A Chinese research team says it has succeeded in producing spider silk using genetically modified caterpillars. This could make it possible to produce spider silk biologically on a larger scale, report the researchers led by Junpeng Mi and Qing Meng from Southwest University in Chongqing in the specialist magazine Matter.
The threads that spiders use to build their webs have long been considered a material with almost magical properties: spider silk is four times as strong as the same amount of steel, it is extremely tear-resistant and can therefore be stretched up to three times its length. The threads are very light, waterproof, resistant to microbiological attacks and yet biodegradable.
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It’s no wonder that people have been finding uses for this very special material since ancient times. Even back then it was used as a wound dressing. Today, at least in the laboratory, it has been possible to package medicinal substances with artificial spider silk on a micro and nano level; NASA would like to use the material in space elevators, and it may also be possible to use it to make particularly light bulletproof vests. Approaches to weaving clothes from real spider silk remained rather temporary in the 19th century. In an experiment at the Victoria and Albert Museum in London, 80 employees collected spider threads for five years, and in 2012 a single spider garment was woven and exhibited.
The problem is: Spiders, at least the ones here, are rather small and their production capacities are limited. Instead, people rely primarily on synthetic fibers, which leave behind harmful microplastics in the environment and are often made from climate-damaging petroleum. Numerous attempts to produce artificial spider silk organically prove to be laborious. In 2010, the company Nexia reported that it had succeeded in implanting spider genes into goats so that they could produce the sought-after silk with their milk. However, the product did not reach market maturity and the company went bankrupt. Nevertheless, intensive research continues on mammalian cells and bacteria.
According to the study authors, a key problem with all of these approaches is that natural spider silk has a kind of “anti-aging skin layer” made of glycoproteins and lipids that protects its web from moisture and strong solar radiation. This problem has now been solved with genetically modified silkworms because they naturally provide their threads with a similar protective layer. According to the study, the result is threads with the greatest tear resistance: they are six times stronger than the actually very robust synthetic Kevlar fibers.
In addition, “silkworms are already the only species that produce silk fiber commercially and on a large scale using well-established breeding techniques,” Junpeng Mi is quoted as saying in a statement in the journal. With this experience, cost-effective spider silk production could also be set up on a large scale.