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Mechanical Performance of Spider Silk Is Robust to Nutrient-Mediated Changes in Protein Composition
journal contribution
posted on 2015-04-13, 00:00 authored by Sean J. Blamires, Chen-Pan Liao, Chung-Kai Chang, Yu-Chun Chuang, Chung-Lin Wu, Todd A. Blackledge, Hwo-Shuenn Sheu, I-Min TsoSpider major ampullate (MA) silk
is sought after as a biomimetic
because of its high strength and extensibility. While the secondary
structures of MA silk proteins (spidroins) influences silk mechanics,
structural variations induced by spinning processes have additional
effects. Silk properties may be induced by spiders feeding on diets
that vary in certain nutrients, thus providing researchers an opportunity
to assess the interplay between spidroin chemistry and spinning processes
on the performance of MA silk. Here, we determined the relative influence
of spidroin expression and spinning processes on MA silk mechanics
when Nephila pilipes were fed solutions with or without
protein. We found that spidroin expression differed across treatments
but that its influence on mechanics was minimal. Mechanical tests
of supercontracted fibers and X-ray diffraction analyses revealed
that increased alignment in the amorphous region and to a lesser extent
in the crystalline region led to increased fiber strength and extensibility
in spiders on protein rich diets.