Physico-chemical properties of functionally adhesive spider silk nanofibres. (2nd February 2023)

• Record Type: Journal Article
• Authors: Joel, Anna-Christin; Rawal, Aditya; Yao, Yin; Jenner, Andrew; Ariotti, Nicholas; Weissbach, Margret; Adler, Lewis; Stafstrom, Jay; Blamires, Sean J.
• Is Part Of: Biomaterials science. Volume 11:Number 6(2023)
• Page Start: 2139
• Page End: 2150
• Publication Date: 2023-02-02
• Subjects: Biomedical materials -- Periodicals; 610.28
• DOI: 10.1039/d2bm01599d
• Languages: English
• ISSNs: 2047-4830

Abstract

Abstract : In nano-scale spider silk fibres, typically secondary protein structures are lost and the silk becomes very compliant. Additionally, due to a changed amino acid composition, a suit of new functionalities can be gained. Abstract : Currently, synthetic fibre production focuses primarily on high performance materials. For high performance fibrous materials, such as silks, this involves interpreting the structure–function relationship and downsizing to a smaller scale to then harness those properties within synthetic products. Spiders create an array of fibres that range in size from the micrometre to nanometre scale. At about 20 nm diameter spider cribellate silk, the smallest of these silks, is too small to contain any of the typical secondary protein structures of other spider silks, let alone a hierarchical skin-core-type structure. Here, we performed a multitude of investigations to elucidate the structure of cribellate spider silk. These confirmed our hypothesis that, unlike all other types of spider silk, it has a disordered molecular structure. Alanine and glycine, the two amino acids predominantly found in other spider silks, were much less abundant and did not form the usual α-helices and β-sheet secondary structural arrangements. Correspondingly, we characterized the cribellate silk nanofibre to be very compliant. This characterization matches its function as a dry adhesive within the capture threads of cribellate spiders. Our results imply that at extremely small scales there may be a limit reached below which a silk will lose its structural, but not functional, integrity. Nano-sized fibres, such as cribellate silk, thus offer a new opportunity for inspiring the creation of novel scaled-down functional adhesives and nano meta-materials.