Stronger silk

Spider silk is tougher and lighter than steel - German scientists have added tiny amounts of metal to spider silk to make it even stronger and more elastic.

The technique could lead to the development of super-tough textiles, surgical thread or artificial tissues such as bones or tendons, the researchers claim.

To make the silk, the researchers borrowed a trick from nature with the goal of further enhancing its properties.

Many insects and other creatures incorporate small amounts of metals such as zinc, manganese, calcium or copper into body parts such as jaws, claws and stingers to make them stiffer and harder. The scientists drew on a technique called atomic layer deposition (ALD) to get zinc, titanium and aluminium ions into the spider silk.

Normally, ALD just leaves a layer of metal oxides on the surface of the treated fibre; treating spider silk in this way, therefore, had little impact on its strength. However, by adapting the technique slightly, the researchers were able to get the metal ions to infiltrate the spider silk and become part of the thread.