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Liquid crystallinity of natural silk secretions

Nature volume 349, pages 596–598 (1991)Cite this article

Abstract

NATURAL silk exhibits a strength and stiffness similar to, and a toughness up to ten times greater than, that of artificial high-performance fibres1–5. These exceptional tensile properties, the optical birefringence of some silk secretions6–9 and the molecular order exhibited by some synthetic polypeptides in solution10 all suggest that natural silk secretions might form liquid-crystalline phases. We have now used polarized-light microscopy to study the secretions from major ampullae of spiders (Nephila clavipes) and from silk glands of silkworms (Bombyx mori). As the concentration is increased by evaporation of water, nematic liquid-crystalline microstructures develop. We deduce that natural silk secretions become liquid crystalline after leaving the gland but before solidifying into a fibre, thus promoting global molecular alignment in the fibre. Our hand-drawn fibres from droplets of secretion, as well as sheared thin films, show a banded microstructure which is indicative of a periodic variation in the direction of molecular alignment11. Both B. mori and N. clavipes, on the other hand, have apparently developed processing routes that ensure uniform molecular alignment: the threads and draglines, respectively, of these species do not show banded microstructures.

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References

  1. Denny, M. J. exp. Biol. 65, 483–506 (1976).

    Google Scholar 

  2. Calvert, P. Nature 340, 266 (1989).

    Article  ADS  Google Scholar 

  3. Vollrath, F. & Edmonds, D. T. Nature 340, 305–307 (1989).

    Article  ADS  Google Scholar 

  4. Gosline, J. M., Denny, M. W. & DeMont, M. E. Nature 309, 551–552 (1984).

    Article  ADS  CAS  Google Scholar 

  5. Prevorsek, D. C. in Polymer Liquid Crystals (eds Ciferri, A., Krigbaum, W. R. & Meyer, R. B.) Ch, 12 (Academic, New York, 1982).

    Google Scholar 

  6. Lucas, F. & Rudall, K. M. in Comprehensive Biochemistry (eds Florkin, M. & Stotz, E. H.) Vol. 26B, Ch. 7 (Elsevier, Amsterdam, 1968).

    Google Scholar 

  7. Magoshi, J., Magoshi, Y. & Nakamura, S. J. appl.Polym. Sci.: appl. Polym. Symp. 41, 187–204 (1985).

    CAS  Google Scholar 

  8. Magoshi, J., Magoshi, Y. & Nakamura, S. Polym. Comm. 26, 60–61 (1985).

    CAS  Google Scholar 

  9. Li, G. & Yu, T. Makromol. Chem. Rapid Comm. 10, 387–389 (1989).

    Article  Google Scholar 

  10. Elliot, A. & Ambrose, E. J. Discuss. Faraday Soc. 9, 246–251 (1950).

    Article  Google Scholar 

  11. Viney, C., Donald, A. M. & Windle, A. H. Polymer 26, 870–878 (1985).

    Article  CAS  Google Scholar 

  12. Tsuda, M. & Suzuki, Y. Proc. natn. Acad. Sci. U.S.A. 80, 7442–7446 (1983).

    Article  ADS  CAS  Google Scholar 

  13. Tamura, T. & Sakate, S. Insect Biochem. 18, 169–175 (1988).

    Article  CAS  Google Scholar 

  14. Lombardi, S. J. & Kaplan, D. L. Polym. Preprints 31(1), 195–196 (1990).

    CAS  Google Scholar 

  15. Billmeyer, F. W. Textbook of Polymer Science Ch. 18 (Wiley, New York, 1984).

    Google Scholar 

  16. Lizuka, E. J. appl. Polym. Sci.: appl. Polym. Symp. 41, 173–185 (1985).

    Google Scholar 

  17. Dobb, M. G. & McIntyre, J. E. Adv. Polym. Sci. 60/61, 61–98 (1984).

    Article  CAS  Google Scholar 

  18. Demus, D. & Richter, L. Textures of Liquid Crystals (Verlag Chemie, Weinheim, 1978).

    Google Scholar 

  19. Lucas, F. Discovery 25, 20–26 (1964).

    Google Scholar 

  20. de Gennes, P. G. The Physics of Liquid Crystals Ch. 4 (Oxford University Press, 1979).

    Google Scholar 

  21. Gray, G. W. & Goodby, J. W. Smectic Liquid Crystals: Textures and Structures 58 (Leonard Hill, Glasgow, 1984)

    Google Scholar 

  22. Zheng, S., Li, G., Yao, W. & Yu, T. Appl. Spectrosc. 43, 1269–1272 (1989).

    Article  ADS  CAS  Google Scholar 

  23. Wilson, R. S. Q. J. microsc. Sci. 104, 557–571 (1962).

    Google Scholar 

  24. Donald, A. M., Viney, C. & Windle, A. H. Polymer 24, 155–159 (1983).

    Article  CAS  Google Scholar 

  25. Marsano, E., Carpaneto, L. & Ciferri, A. Molec. Cryst. liq. Cryst. 158B, 267–278 (1988).

    CAS  Google Scholar 

  26. Fried, F. & Sixou, P. Molec. Cryst. liq. Cryst. 158B, 163–184 (1988)

    CAS  Google Scholar 

  27. Ernst, B. & Navard, P. Macromolecules 22, 1419–1422 (1989).

    Article  ADS  CAS  Google Scholar 

  28. Dobb, M. G., Johnson, D. J. & Saville, B. P. J. Polym. Sci.: Polym. Symp. 58, 237–251 (1977).

    CAS  Google Scholar 

  29. Roche, E. J., Allen, S. R., Fincher, C. R. & Paulson, C. Molec. Cryst. liq. Cryst. 153, 547–552 (1987).

    CAS  Google Scholar 

  30. Cokendolpher, J. C. & Brown, J. D. Ent. News 96, 114–118 (1985).

    Google Scholar 

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Authors and Affiliations

  1. Department of Materials Science and Engineering FB-10, University of Washington, Seattle, Washington, 98195, USA

    Keven Kerkam & Christopher Viney

  2. US Army Research, Development and Engineering Center, Natick, Massachusetts, 01760, USA

    David Kaplan & Stephen Lombardi

Authors
  1. Keven Kerkam
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  2. Christopher Viney
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  3. David Kaplan
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  4. Stephen Lombardi
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Kerkam, K., Viney, C., Kaplan, D. et al. Liquid crystallinity of natural silk secretions. Nature 349, 596–598 (1991). https://doi.org/10.1038/349596a0

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