Shear-Induced β-Crystallite Unfolding in Condensed Phase Nanodroplets Promotes Fiber Formation in a Biological Adhesive
| Autor: | Georg Mayer, Peter Fratzl, Nils Horbelt, Matthew J. Harrington, Stephan Schmidt, Santiago J. Garcia, Marlies Nijemeisland, Alexander Baer |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
General Physics and Astronomy 02 engineering and technology Spectrum Analysis Raman 010402 general chemistry 01 natural sciences Protein structure X-Ray Diffraction Adhesives Helminths Phase (matter) Spectroscopy Fourier Transform Infrared Animals General Materials Science Amino Acid Sequence Fiber chemistry.chemical_classification Shearing (physics) General Engineering Proteins Polymer 021001 nanoscience & nanotechnology 0104 chemical sciences Chemical engineering chemistry Nanoparticles Stress Mechanical Self-assembly Adhesive Crystallite Crystallization Rheology 0210 nano-technology |
| Zdroj: | ACS Nano. 13:4992-5001 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/acsnano.9b00857 |
| Popis: | Natural materials provide an increasingly important role model for the development and processing of next-generation polymers. The velvet worm Euperipatoides rowelli hunts using a projectile, mechanoresponsive adhesive slime that rapidly and reversibly transitions into stiff glassy polymer fibers following shearing and drying. However, the molecular mechanism underlying this mechanoresponsive behavior is still unclear. Previous work showed the slime to be an emulsion of nanoscale charge-stabilized condensed droplets comprised primarily of large phosphorylated proteins, which under mechanical shear coalesce and self-organize into nano- and microfibrils that can be drawn into macroscopic fibers. Here, we utilize wide-angle X-ray diffraction and vibrational spectroscopy coupled with in situ shear deformation to explore the contribution of protein conformation and mechanical forces to the fiber formation process. Although previously believed to be unstructured, our findings indicate that the main phosphorylated protein component possesses a significant β-crystalline structure in the storage phase and that shear-induced partial unfolding of the protein is a key first step in the rapid self-organization of nanodroplets into fibers. The insights gained here have relevance for sustainable production of advanced polymeric materials. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|