Natural spider silk fibers exhibit mechanical and biological properties unmatched by most other known natural or man-made fibrous materials [1, 2]. In comparison to Kevlar, the strongest synthetic polymer fiber material to date, spider silk can absorb three times more energy before it breaks. Combined with their good biocompatibility and biodegradability, silk materials offer versatile applications in high-tech fields. To better understand the natural process, we recombinantly co-produced two different spider silk proteins in E. coli, yielding a mixture of homo- and heterodimers. Intermolecular interactions of these proteins in aqueous spinning dopes enabled their self-assembly into higher-order structures [3, 4]. Upon biomimetic spinning, nature-like performing fibers could be obtained concerning all important mechanical features such as tensile strength, elasticity, Young’s modulus as well as toughness [3]. Our findings emphasize the importance of protein interplay for functional complexity, ultimately providing a road map to design green high-performance fibers.

References
[1] M. Heim, D. Keerl, T. Scheibel  Angew. Chem. Int. Ed 2009, 48, 3584-3596
[2] A. Heidebrecht, L. Eisoldt, J. Diehl, A. Schmidt, M. Geffers, G. Lang, T. Scheibel Advanced Materials 2015, 27, 2189–2194.
[3] F. Hagn, L. Eisoldt, J. Hardy, C. Vendrely, M. Coles, T. Scheibel, H. Kessler Nature 2010, 465, 239-242
[4] M. Saric, L. Eisoldt, V. Döring, T. Scheibel Advanced Materials 2021, 33, 2006499