Press Release: Nanofibrillar Structure of Recluse Silk

(a) Female recluse spider surrounded by its web. (b) Microscope image of recluse silk fiber surface showing the nanofibrils aligned parallel to the fiber. © Penetration of the fiber with the extremely sharp tip.

Researchers revealed the inner make-up of a single fiber of the web of a brown recluse spider. These fibers are one hundred times thinner than a human hair. Never¬theless, each one is built like a cable, with thousands of thinner threads inside — rather than being made of a single piece.
The silk fibers of the spider web are as strong as steel, yet five times lighter. Scientists and laymen alike have wondered for decades what makes this material so amazingly strong. Dinidu Perera and his colleagues now got one step closer to a better understanding. Using electron and atomic force microscopes they found that the entire fiber is made up of about 2,500 nanofibrils, each 10,000 times thinner than a human hair. They then used extremely sharp silicon needles to pierce a single spider silk fiber. They found that the nanofibrils inside a silk fiber come apart relatively easily, which made it surprisingly easy to penetrate the fiber. Measuring the small pe-netration force precisely, the researchers were able to determine the sticking force between nano¬fibrils for the first time. Although the cable-like silk is as strong as steel, the individual fibrils inside do not stick together more strongly than sticky tape. This means that the fibrils can slide past each other when the silk fiber bends or make turns, and prevent un¬necessary fiber damage.
The detailed understanding of this wonder material newly developed by the team around Hannes Schniepp at William & Mary will help ongoing efforts to make synthetic spider silk. The needle method they invent¬ted has the potential for early diagnostics of cancers or osteo-arthritis. The story just appeared in Small, a well-known journal for nanoscale materials research.

Link: Publication.

• Link to scientific paper
• More about our silk research
• All Publications of the Schniepp group