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Hierarchical Assembly Investigations and Multiscale Characterization of Protein-based Materials

Insights from Whey Protein Nanofibrils and Recombinant Spider Silk Microspheres

Time: Thu 2023-06-15 13.00

Location: E3, Osquars backe 14, Stockholm

Video link:

Language: English

Subject area: Biotechnology

Doctoral student: Eirini Ornithopoulou , Proteinteknologi

Opponent: Universitetslektor Tim Melander Bowden, Uppsala universitet

Supervisor: Professor My Hedhammar, Proteinteknologi, Centrum för Bioprocessteknik, CBioPT, Science for Life Laboratory, SciLifeLab, Albanova VinnExcellence Center for Protein Technology, ProNova; Doktor Thomas Crouzier, Glykovetenskap; Professor Christina Divne, Industriell bioteknologi, Strategiskt Centrum för Biomimetiska Material, BioMime, Albanova VinnExcellence Center for Protein Technology, ProNova

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QC 2023-05-17


Protein-based materials, with their unique properties of combining high strength, while maintaining elasticity, and their inherent biocompatibility, hold immense potential for various applications. In order to harness these properties, we need to understand and control how protein building blocks come together to form hierarchically structured materials. Using critical thinking when combining different proteins may lead to advanced materials with synergistic effects that can tackle complex problems such as targeted drug delivery. This thesis presents an investigation into the behavior of some protein-based materials, specifically whey protein isolate nanofibrils, β-lactoglobulin peptide fragment assemblies, and recombinant spider silk microspheres.

In Paper I, the hierarchical assembly and packing behavior of whey protein nanofibrils were in situ investigated using a Liquid Bridge Induced Assembly setup and X-ray Scattering, along with Atomic Force Microscopy and Scanning Electron Microscopy. The results demonstrated that the alignment of straight and curved fibrils was affected by temperature and fibril size, providing insights into assembly dynamics for future material production.

In Paper II, the impact of nanoscale features of whey protein nanofibrils on the morphology of films was investigated. It was found that controlling fibril size and employing fast-drying protocols could manipulate macroscale features without sacrificing the functional properties of the nanofibrils.

In Paper III, the nanoscale morphology, molecular arrangement, and polymorphism of protein nanofibrils formed by a synthetic peptide fragment derived from β-lactoglobulin were examined. Β-lactoglobulin is the only nanofibril forming component in whey protein isolate. Results suggested that polymorphism stems from protofilament packing differences at the nanoscale, and a possible parallel steric zipper packing.

In Paper IV, the self-assembly behavior of a recombinant spider silk protein in physiological like buffer and with the addition of hyaluronic acid was explored. The self-assembled FN-silk microspheres demonstrated a fibrillar or porous mesostructure. 2D and 3D cell culture trials show that the microspheres could have potential applications in biomedicine.

Taken together, the acquired knowledge will contribute to our fundamental understanding of protein-based materials, especially those similar to PNF-based and recombinant spider silk-based materials and inform the design of improved and innovative materials in biomanufacturing, such as functional textiles and surface biofunctionalization.