Final Report Summary - SABIP (Silks as Biomimetic Ideals for Polymers: SABIP)
Silk is a non-perishable agricultural product with an unparalleled history as high-value and wealth-creating fibre and textile. Our ERC funded study Silks as Biomimetic Ideals for Polymers set out to scientifically examine specific aspects of silks in detail while at the same time probing the possibilities of silks and silk derivatives as commercial materials in the 21st century. Our studies confirmed that silks are remarkably tough fibres as well as materials that could be ecologically sustainable if properly managed. Filaments that can match the best of man-made fibres are produced with water as the solvent, with pure proteins as the major structural components and are all processed under benign ambient temperatures and pressures. Silks are biocompatible and biodegradable, which makes them both important medical materials as well as models for designing novel, fully sustainable polymers. In addition silks, being protein based, provide unique models for protein folding and some of the fundamentals of protein structure/properties/function relationships. Finally, as non-perishable agricultural products, silks are notable for combining good land-use with high socio-economic value.
With all these interesting and important silk properties in mind, our study focused on 4 closely interwoven themes. Firstly we explored the natural diversity of silks from many taxa ranging from spiders and insects to shrimps and bees. Secondly we tested the materials properties of a wide range of silks in great detail using a unique combination of state-of-the-art analytical equipment and insights. Thirdly we used advanced mathematical modeling to theoretically analyse the full hierarchy of a silk’s structure-property-function relationships obtained from empirical measurements. Fourthly we interacted with many producers of silks and manufacturers of silk products in order to further the sustainable use of silks and the development of novel silk products based on scientific insights. Significant progress was made in all four areas demonstrated by selected exemplary studies. In the field of bio-exploration we discovered and analyzed a novel marine underwater silk that combines aspects of spider thread and barnacle glue. The study of unusual nano-scale filament or permanently liquid-droplet silks led to the discovery of specialist adaptations with important wider implications. A wide range of silkworm-moth cocoons provided novel and highly technical insights into the construction of outstanding composite material with commercial applications. A new way to unravel the cocoons led to a patent granted with consequences for silk industries in emerging markets.
Our materials testing laboratory provides a superb state-of-the-art analysis facility for bio-materials where, for example, millimeter lengths of micron-scale filaments (or mm cubes of biopsy or composite samples) can be analyzed over the full range of their mechanical, thermal and chemical properties. Insights gained from such studies demonstrated the importance of water only for the flow properties of un-spun silks but also for the properties of the fully formed thread. Importantly, these studies also showed that native (natural) pre-spinning silk behave very different (by orders of magnitude) from silk-solutions that had been obtained by dissolving spun silks. This observation led to deeper understanding of silk-protein folding, which is leading to the establishment of silk proteins as models to study fundamentals of protein folding. Our modeling approaches further facilitate the establishment and analysis of hypotheses pertaining to protein structure-properties-function relationships based on empirical data. Importantly, this research on silk protein conformations and their transitions demonstrated the value of a tightly interactive group effort integrating experiment and modeling when studying structure-function relationships in a biomaterial.
Last but not least, throughout the grant we have pro-actively engaged existing producers as well as actual and potential end users of silk products. This allowed us to interactively communicate our scientific discoveries while at the same time acquiring important insights into the needs and technical requirements of the wider silk market. A much appreciated ERC proof of concept grant allowed us to successfully promote the commercial applications of our fundamental insights. This includes the establishment of a data-base and an extended Life Cycle Analysis of service to the global silk industry. Our concept of an eco-SWOT analysis will allow the defining, branding and marketing of ‘Sustainable Silks’ in Europe by allowing researchers, producers and users to forge valuable links between academic insights and commercial realities in a market that is already adding ca €80Bn value to the ca €2Bn of raw silk.
With all these interesting and important silk properties in mind, our study focused on 4 closely interwoven themes. Firstly we explored the natural diversity of silks from many taxa ranging from spiders and insects to shrimps and bees. Secondly we tested the materials properties of a wide range of silks in great detail using a unique combination of state-of-the-art analytical equipment and insights. Thirdly we used advanced mathematical modeling to theoretically analyse the full hierarchy of a silk’s structure-property-function relationships obtained from empirical measurements. Fourthly we interacted with many producers of silks and manufacturers of silk products in order to further the sustainable use of silks and the development of novel silk products based on scientific insights. Significant progress was made in all four areas demonstrated by selected exemplary studies. In the field of bio-exploration we discovered and analyzed a novel marine underwater silk that combines aspects of spider thread and barnacle glue. The study of unusual nano-scale filament or permanently liquid-droplet silks led to the discovery of specialist adaptations with important wider implications. A wide range of silkworm-moth cocoons provided novel and highly technical insights into the construction of outstanding composite material with commercial applications. A new way to unravel the cocoons led to a patent granted with consequences for silk industries in emerging markets.
Our materials testing laboratory provides a superb state-of-the-art analysis facility for bio-materials where, for example, millimeter lengths of micron-scale filaments (or mm cubes of biopsy or composite samples) can be analyzed over the full range of their mechanical, thermal and chemical properties. Insights gained from such studies demonstrated the importance of water only for the flow properties of un-spun silks but also for the properties of the fully formed thread. Importantly, these studies also showed that native (natural) pre-spinning silk behave very different (by orders of magnitude) from silk-solutions that had been obtained by dissolving spun silks. This observation led to deeper understanding of silk-protein folding, which is leading to the establishment of silk proteins as models to study fundamentals of protein folding. Our modeling approaches further facilitate the establishment and analysis of hypotheses pertaining to protein structure-properties-function relationships based on empirical data. Importantly, this research on silk protein conformations and their transitions demonstrated the value of a tightly interactive group effort integrating experiment and modeling when studying structure-function relationships in a biomaterial.
Last but not least, throughout the grant we have pro-actively engaged existing producers as well as actual and potential end users of silk products. This allowed us to interactively communicate our scientific discoveries while at the same time acquiring important insights into the needs and technical requirements of the wider silk market. A much appreciated ERC proof of concept grant allowed us to successfully promote the commercial applications of our fundamental insights. This includes the establishment of a data-base and an extended Life Cycle Analysis of service to the global silk industry. Our concept of an eco-SWOT analysis will allow the defining, branding and marketing of ‘Sustainable Silks’ in Europe by allowing researchers, producers and users to forge valuable links between academic insights and commercial realities in a market that is already adding ca €80Bn value to the ca €2Bn of raw silk.