Five times the tensile strength of steel and triple that of the currently best synthetic fibers: Spider silk is a fascinating material. But no one has thus far succeeded in producing the super fibers synthetically. How do spiders form long, highly stable and elastic fibers from the spider silk proteins stored in the silk gland within split seconds? Scientists from the Technische Universitaet Muenchen (TUM) and the University of Bayreuth have now succeeded in unraveling the secret. They present their results in the current issue of the prestigious scientific journal Nature.
"The high elasticity and extreme tensile strength of natural spider silk are unmatched, even by fibers produced from pure spider silk proteins," says Professor Horst Kessler, Carl-von-Linde Professor at the Institute for Advanced Study of the TU Muenchen. That highlights a key question in the artificial production of stable spider silk fibers: How do spiders manage to keep the high concentrations of raw material available in the silk gland, ready to produce the high tensile strength fiber at a moment's notice. Thomas Scheibel has been pursuing the secret of spider silk for years, until 2007 at TUM and since then at the University of Bayreuth.
Spider silk consists of protein molecules, long chains comprising thousands of amino-acid elements. X-ray structure analyses show that the finished fiber has areas in which several protein chains are interlinked via stable physical connections. These connections provide the high stability. Between these connections are unlinked areas that give the fibers their great elasticity.
The situation within the silk gland is, however, very different: The silk proteins are stored in high concentrations in an aqueous environment, awaiting deployment. The areas responsible for interlinking may not approach each other too closely; otherwise the proteins would clump up instantaneously. Hence, these molecules must have some kind of sp
|Contact: Andreas Battenberg|
Technische Universitaet Muenchen