Spider silk alone is stronger than steel, but researchers in Halle Germany have found that it can be made even stronger. A new paper, published today in Science reports that spider silk can be infused with metals such as aluminum, zinc and titanium.

Metals are not unheard of as strengtheners in the natural world. Proteins within jaw of the Nereis marine worm, for instance, contain both copper and zinc. But such structures are usually found in rigid body parts, such as claws or stingers. So scientists wanted to try infusing something flexible with metal. For that, they turned to drag line silk—that's used to form the outer rim and spokes of the web – from the Araneaus spider.

Just dipping the spider silks, which are made of complex proteins, into room temperature metal solutions didn't add much strength, so the researchers used natural enemies of the strands: heat and moisture. By blasting the strands with hot water vapors, the researchers were able to break down some of the protein bonds in the silk. Then, after exposing the damaged strands to vapor containing aluminum, zinc or titanium, some of the metal molecules attached to the broken protein bonds.

"Unlike native silks," the researchers conclude, "which are highly sensitive to environmental conditions such as humidity and temperature, the metal-infiltrated silks…are hardly affected." The researchers don't discuss prospects for genetically engineering the spiders, but just by improving web they already produce, scientists could develop tougher textiles, super surgical threads, artificial human tissues, and in the case of any serum-sipping villains, defense against the Green Goblin.

Sorry, Spidey, guess your secret is out of the bag.

Listen to a podcast about this study.

Image courtesy of Alex Scarcella via Flickr