With a raised global awareness of industrial environmental pollution, polymer research is focusing on green biopolymers. The spinning gland of spiders and silk moths is the holy grail in green extrusion, as silk is spun at ambient and water-based conditions. This is achieved by finely tuned spinning parameters in the silk gland (pH, ion concentration, stress and water removal), whereby the silk solution is converted into a solid fibre. To date, no one has ever succeeded in spinning at these ambient conditions, used in the natural spinning system.
In this project, one missing spinning parameter was investigated, namely small molecules, in the form of polyphenolic compounds that are co-extruded with the silk. We anticipate that small molecules assist in the silk alignment and may even induce β-sheet aggregation by removing the water necessary for converting the silk protein solution into a solid fibre during spinning.
The objectives of the project were twofold: (1) investigation of the polyphenol-induced conversion of proteins to β-sheet structures, necessary for a successful transformation of a protein solution into a solid material and (2) applying this knowledge for the cold extrusion of protein-based materials.
During the project, it was clear that the synthesis and purification of a small molecular compound accompanying the silk of the spider Nephila edulis was the key challenge of this project and required our full attention in order to study the small molecule-protein interactions. We successfully managed to produce this small molecule in large quantities and in its pure form, a major scientific breakthrough, paving the way for application-oriented scientific work. Furthermore, we found that this compound revealed antibacterial properties and therefore can be used as a new antibiotic. It is clear that this research opened many new possibilities and future perspectives, all which will be continued through continued research efforts beyond the Marie Curie fellowship.
