Nicola Pugno from the University of Trento wondered what would happen if his team combined one of nature's strongest materials—spider silk—and one of man's strongest creations—graphene. (Why wouldn't you want to make spiders even more formidable?)
The team set about testing this combination by spraying five spiders with a water-graphene particle mixture. They also sprayed ten more spiders with a water-carbon nanotube mixture.
Graphene is a carbon-based material that is 200 times stronger than steel and thinner than human hair. Carbon nanotubes are also extremely thin, strong and made of carbon: they resemble rolled-up chicken wire because of the way that carbon bonds with itself.
Somehow, the spiders managed to incorporate the carbon-based particles into their silk for making webs. Some of the spiders didn't achieve this as effectively and their webs suffered as a result. Four spiders perished quickly after being sprayed with the mixture. However, incredibly, some spiders interwove these carbon gifts into their webs to create silk around 3.5 times as tough and strong as the unaltered silk of the giant riverine orb spider.
It is still unknown how the spiders integrated the carbon into their silk. At the moment, it is speculated that the spiders may weave the carbon fibers into their silk as they spin it out. Alternatively, the spiders may be absorbing the nanotubes and infusing it into the silk-making process.
The study, published as a pre-print edition here, summarized that the spiders sprayed with the carbon nanotube mixture produced the strongest webs. The strength is comparable to the strongest carbon fibers or the material that limpet's teeth are made from.
This study is exciting for the future of fiber-creation. The possibilities of infusing man-made materials into living things are opening up new possibilities for producing bionic materials. What else could a spider mop up and integrate into spider silk? "This concept could become a way to obtain materials with superior characteristics," Pugno says on the subject of bionic materials.
[Via Arxiv, New Scientist]