TY - JOUR
T1 - Fine Structural Analysis of Degummed Fibroin Fibers Reveals Its Superior Mechanical Capabilities
AU - Eliaz, D.
AU - Kellersztein, I.
AU - Miali, M. E.
AU - Benyamin, D.
AU - Brookstein, O.
AU - Daraio, C.
AU - Wagner, H. D.
AU - Raviv, U.
AU - Shimanovich, U.
N1 - Publisher Copyright:
© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.
PY - 2024
Y1 - 2024
N2 - Bombyx mori silk fibroin fibers constitute a class of protein building blocks capable of functionalization and reprocessing into various material formats. The properties of these fibers are typically affected by the intense thermal treatments needed to remove the sericin gum coating layer. Additionally, their mechanical characteristics are often misinterpreted by assuming the asymmetrical cross-sectional area (CSA) as a perfect circle. The thermal treatments impact not only the mechanics of the degummed fibroin fibers, but also the structural configuration of the resolubilized protein, thereby limiting the performance of the resulting silk-based materials. To mitigate these limitations, we explored varying alkali conditions at low temperatures for surface treatment, effectively removing the sericin gum layer while preserving the molecular structure of the fibroin protein, thus, maintaining the hierarchical integrity of the exposed fibroin microfiber core. The precise determination of the initial CSA of the asymmetrical silk fibers led to a comprehensive analysis of their mechanical properties. Our findings indicate that the alkali surface treatment raised the Young′s modulus and tensile strength, by increasing the extent of the fibers’ crystallinity, by approximately 40 % and 50 %, respectively, without compromising their strain. Furthermore, we have shown that this treatment facilitated further production of high-purity soluble silk protein with rheological and self-assembly characteristics comparable to those of native silk feedstock, initially stored in the animal′s silk gland. The developed approaches benefits both the development of silk-based materials with tailored properties and the proper mechanical characterization of asymmetrical fibrous biological materials made of natural building blocks.
AB - Bombyx mori silk fibroin fibers constitute a class of protein building blocks capable of functionalization and reprocessing into various material formats. The properties of these fibers are typically affected by the intense thermal treatments needed to remove the sericin gum coating layer. Additionally, their mechanical characteristics are often misinterpreted by assuming the asymmetrical cross-sectional area (CSA) as a perfect circle. The thermal treatments impact not only the mechanics of the degummed fibroin fibers, but also the structural configuration of the resolubilized protein, thereby limiting the performance of the resulting silk-based materials. To mitigate these limitations, we explored varying alkali conditions at low temperatures for surface treatment, effectively removing the sericin gum layer while preserving the molecular structure of the fibroin protein, thus, maintaining the hierarchical integrity of the exposed fibroin microfiber core. The precise determination of the initial CSA of the asymmetrical silk fibers led to a comprehensive analysis of their mechanical properties. Our findings indicate that the alkali surface treatment raised the Young′s modulus and tensile strength, by increasing the extent of the fibers’ crystallinity, by approximately 40 % and 50 %, respectively, without compromising their strain. Furthermore, we have shown that this treatment facilitated further production of high-purity soluble silk protein with rheological and self-assembly characteristics comparable to those of native silk feedstock, initially stored in the animal′s silk gland. The developed approaches benefits both the development of silk-based materials with tailored properties and the proper mechanical characterization of asymmetrical fibrous biological materials made of natural building blocks.
KW - Degumming
KW - Mechanical properties
KW - Protein self-assembly
KW - Silk fibers
KW - β-sheet conformation
UR - http://www.scopus.com/inward/record.url?scp=85204786452&partnerID=8YFLogxK
U2 - 10.1002/cssc.202401148
DO - 10.1002/cssc.202401148
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C2 - 39023515
AN - SCOPUS:85204786452
SN - 1864-5631
JO - ChemSusChem
JF - ChemSusChem
ER -