Press Release: Recluse Spider’s Super-Thin and Strong Silk Ribbons
| October 8, 2013 — By Hannes C. Schniepp
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Who knew such a venomous little creature could harbor so many potential benefits for humanity? The recluse spider (see top figure) is an all American spider greatly feared for its highly venomous bite. But now our team in collaboration with Fritz Vollrath from the University of Oxford has revealed that its fibers have highly unusual structure and properties. On the one hand, this provides a key to unraveling the secrets of the molecular structure of silk. On the other hand, this will most likely lead to novel medical and engineering applications for silks. This work has recently been published in the prestigious journal Advanced Materials.
We all have heard much about the outstanding strength and toughness of spider silk threads. And the threads of the brown recluse spider have all those great properties, too. But her threads are super thin ribbons and not the round fibers of all the other spiders (see bottom figure).
In collaboration with Fritz Vollrath, we have now manually extracted fibers from recluse spiders for the first time and revealed the unique properties of this silk. We modified a so-called atomic force microscope to measure the rigidity of a single recluse fiber and found that this ribbon—one thousand times thinner than a human hair—still features the same strength and toughness as other silks.
The extreme thinness allows this ribbon-fiber to combine its outstanding mechanical stiffness with the ability to perfectly adapt to surfaces of other materials, and this gives rise to unprecedented adhesive properties. We also found that the surface of the silk ribbons is covered with tiny, dot-like surface elevations that the research team suspects further enhance adhesion.
This recent discovery is expected to have implications for the development of novel sticky cling films and also thin-film medical devices such as implantable sensors and electronic devices, where silk and thin silk films are not only used for their strength but also for their outstanding biocompatibility.