title: Silk protein aggregation kinetics revealed by Rheo-IR.
abstract: The remarkable mechanical properties of silk fibres stem from a multi-scale hierarchical structure created when an aqueous protein "melt" is converted to an insoluble solid via flow. To directly relate a silk protein's structure and function in response to flow, we present the first application of a Rheo-IR platform, which couples cone and plate rheology with attenuated total reflectance infrared spectroscopy. This technique provides a new window into silk processing by linking shear thinning to an increase in molecular alignment, with shear thickening affecting changes in the silk protein's secondary structure. Additionally, compared to other static characterization methods for silk, Rheo-IR proved particularly useful at revealing the intrinsic difference between natural (native) and reconstituted silk feedstocks. Hence Rheo-IR offers important novel insights into natural silk processing. This has intrinsic academic merit, but it might also be useful when designing reconstituted silk analogues alongside other polymeric systems, whether natural or synthetic.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK. Electronic address: maxime.boulet.audet@gmail.com.
authors.forename: Maxime
authors.initials: M
authors.lastname: Boulet-Audet
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK; ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, UK.
authors.forename: Ann E
authors.initials: AE
authors.lastname: Terry
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Fritz
authors.initials: F
authors.lastname: Vollrath
authors.affiliation: University of Sheffield, Department of Materials Science and Engineering, Sheffield, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Holland
mesh_terms: D000818:Animals; D012831:Bombyx; D055119:Elastic Modulus; D007700:Kinetics; D020836:Protein Structure, Quaternary; D012212:Rheology; D047011:Silk / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014783:Viscosity
chemical_list: D047011:Silk
keywords: Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy; Bombyx mori; Native silk; Reconstituted silk fibroin; Rheology