What's next? The silk racing car?

Spider silk is itself a composite material and, over the last decade, there has been a significant increase in scientific literature about it. This interest is due to its impressive mechanical properties, at a time when biomaterials and biomimetics are both exciting interest in the field of materials research.

The US Army is interested in the potential of the material for bulletproof vests, armour, tethers and other applications. Web dragline silk can be extended 30-50% of its length before it breaks.

At UC in Santa Barbara, California, the focus is on learning how the protein folds, and how it is organized in the silk fibre. Using atomic force microscopy and a molecular puller, the researchers are getting clues from imaging and pulling the protein. These observations help the researchers to model what is happening in the silk gland when silk proteins are assembling into spider dragline silk fibres.

They found that, when the protein unfolds, it is modular. It has sacrificial bonds that open, and then reform when the load lifts. This follows a pattern that has been found in other loadbearing proteins.