Nanovoid formation induces property variation within and across individual silkworm silk threads

Abstract

Silk is a unique fiber, having a strength and toughness that exceeds other natural fibers. While inroads have been made in our understanding of silkworm silk structure and function, few...

Physico-chemical properties of functionally adhesive spider silk nanofibres

“…This was done by locating a single cribellate nanofibre of B. longinqua on top of a larger fibre via AFM. Once identified by its characteristic knot structure, the AFM peak force tapping mode was used following procedures outlined by Craig et al 47 The fibre was repeatedly probed at specific points along its surface to generate a series of AFM images, from which the Derjaguin–Muller–Toporov (DMT) modulus, a measure of elasticity, of the fibre was calculated. There was no discernible difference in the elasticity between the larger fibre and the cribellate fibre resting on it using this method, with both fibres being extremely compliant with a DMT modulus of about 40 to 45 MPa (Fig.…”

Bending–Spinning Produces Silkworm and Spider Silk with Enhanced Mechanical Properties

“…During bending over the entire range of angles, the combined influences of factors beneficial and detrimental to the mechanical properties resulted in the initial increase and subsequent decrease in the silk strength, elastic modulus, and toughness; and when bending angle was 67.5°–90°, the three microstructures crystallinity, crystal size, and orientation of the FS-S silk reach a certain equilibrium state, which can make the best mechanical properties of silk. Some studies have uncovered that nanovoids can also affect the performance of silkworm silk. − Nevertheless, no visible nanovoids were discovered in the cross section of FS-S silk subjected to bending at various angles (Figure S13). Consequently, the changes in microscopic crystal structure of silk protein are most likely the main reasons for the changes in the mechanical properties of silk.…”

Grand challenges in arachnid genetics and biomaterials

“…Nevertheless, when scaled down to the atomistic level, no such correlations hold (Van Beek et al, 2002;Romer and Scheibel, 2008;Koebley et al, 2017;Blamires et al, 2022). We do not know why there is a disjunction between the nanoscale and bulk fibre properties (Blamires et al, 2022;Craig et al, 2022). More research is clearly needed to better understand how silk properties are induced across the different scales.…”

“…The accumulated work on spider silk means we now understand the genetic mechanisms by which environmental factors can affect differential protein (in spiders these are called spidroins, a portmanteau of spider fibroins) expression and biomaterial production, and the intricate complexity of these on phenotypic and extended phenotypic expressions. Recent advancements in genetic and other experimental (see Sane and McHenry, 2009;Craig et al, 2019;Craig et al, 2022;Blamires et al, 2023a) and computational (e.g. Blamires and Sellers, 2019;Craig et al, 2020;von Reumont et al, 2022) tools mean that we can form solid testable hypotheses to explain the evolutionary trajectories of spiders and other arachnids, and how the expressed biomaterial products, including various types of silks, glues, venoms, cuticular molecules and pigments, influence those trajectories (Piorkowski and Blackledge, 2017;von Reumont et al, 2022); Joel et al, 2023).…”