Scientists Close-In on Artificial Spider Silk

MAY 8, 2012

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X-ray scattering images of a Nephila clavipes spider silk orientated perpendicular to the incoming beam (top) and along the fiber axis (bottom). From C. J. Benmore et al., Phys,. Rev. Lett. 108, 178102 (2012). ©2012 American Physical Society.

From Talking Points Memo (TPM)

By Carl Franzen May 7, 2012

Paging Peter Parker: Scientists have taken another step closer to producing viable artificial spider silk by zooming-in on the nanoscopic structure of the natural, spider-made stuff, using … [high-energy] x-ray beams [at the U.S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne National Laboratory].

And as it turns out, despite the intricate and deliberate patterns woven by common orb spiders, the strongest part of their silk — the threads called dragline silk, which are used to create the scaffolding of the entire web — are mostly made up of extremely random and disordered atoms on the nanoscale, according to the results of a new study by scientists in Arizona and Illinois.

In fact, between 85 and 90 percent of orb spiders’ dragline silk fibers are “amorphous regions,” comprised of random, disorganized atoms, which researchers believe are responsible for providing the silk with its extreme elasticity.

The remaining 15 to 10 percent of the silk is a highly-orderly crystalline lattice structure of atoms which gives the silk it’s amazing strength — as strong as steel…

“These techniques we develop are getting us closer and closer to know the exact molecular structures within natural spider silk,” said Jeff Yarger, a biochemistry professor at Arizona State University and one of the lead researchers of the study, in an email to TPM…

…“Previously scientists had concentrated on the more ordered crystalline regions even though they form a minority of the fiber,” said Chris Benmore, an [Argonne] x-ray scientist on the project…

In this case, the APS high-energy x-rays allowed Yarger and his colleagues [working at Argonne X-ray Science Division x-ray beamline 11-ID-C] to achieve an unprecedented level of detail when it came to imaging the amorphous regions of spider silk, zooming in to 10 million times magnification.

“We have recently developed a very powerful high energy x-ray probe at the APS which does not destroy the sample (which is a problem with lower energy x-rays) and provides a detailed insight into both the amorphous and crystalline regions of the spider silk,” Benmore explained.

See: C. J. Benmore1,2, T. Izdebski2, and J. L. Yarger2*, “Total X-Ray Scattering of Spider Dragline Silk,” Phys. Rev. Lett. 108, 178102 (27 April 2012). DOI: 10.1103/PhysRevLett.108.178102

Author affiliations: 1Argonne National Laboratory, 2Arizona State University

Correspondence: *jyarger@gmail.com

The U.S. Department of Energy (DOE); Argonne National Laboratory, under Contract No. DE-AC02-06CH11357; and DOE-EPSCoR, under Contract No. DE-SC0004791 supported this work. Professor J. L. Yarger would like to acknowledge spider silk research support from the Department of Defense, AFOSR (FA9550-10-1-0275), and the U.S. National Science Foundation (DMR-0805197 and CHE-1011937). Also, we would like to acknowledge x-ray diffraction support from NNSA CDAC under Grant No. DE-FC52-08NA28554. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. DOE Office of Science under Contract No. DE-AC02-06CH11357.

The Argonne press release can be read here.

See also: Physorg.com, R&D (Government Research Laboratories/Argonne National Laboratory [Doe] News), nanowerk

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