Self-Assembly of Polysaccharides Gives Rise to Distinct Mechanical Signatures in Marine Gels
Autor: | Jasna Brujic, Vesna Svetličić, Galja Pletikapić, Miklós S.Z. Kellermayer, Ünige Murvai, Herbert Lannon |
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Rok vydání: | 2014 |
Předmět: |
Biophysics
02 engineering and technology 010402 general chemistry Fibril Polysaccharide 01 natural sciences Molecular level Polysaccharides Carbohydrate Conformation Elasticity (economics) Diatoms chemistry.chemical_classification Atomic force microscopy Intermolecular force Force spectroscopy 021001 nanoscience & nanotechnology 0104 chemical sciences Crystallography marine gel polysaccharides self-assembly force spectroscopy AFM chemistry Chemical physics Stress Mechanical Self-assembly Molecular Machines Motors and Nanoscale Biophysics 0210 nano-technology Gels |
Zdroj: | Biophysical Journal. 107:355-364 |
ISSN: | 0006-3495 |
Popis: | Marine-gel biopolymers were recently visualized at the molecular level using atomic force microscopy (AFM) to reveal fine fibril-forming networks with low to high degrees of cross-linking. In this work, we use force spectroscopy to quantify the intra- and intermolecular forces within the marine-gel network. Combining force measurements, AFM imaging, and the known chemical composition of marine gels allows us to identify the microscopic origins of distinct mechanical responses. At the single-fibril level, we uncover force-extension curves that resemble those of individual polysaccharide fibrils. They exhibit entropic elasticity followed by extensions associated with chair-to-boat transitions specific to the type of polysaccharide at high forces. Surprisingly, a low degree of cross-linking leads to sawtooth patterns that we attribute to the unraveling of polysaccharide entanglements. At a high degree of cross-linking, we observe force plateaus that arise from unzipping, as well as unwinding, of helical bundles. Finally, the complex 3D network structure gives rise to force staircases of increasing height that correspond to the hierarchical peeling of fibrils away from the junction zones. In addition, we show that these diverse mechanical responses also arise in reconstituted polysaccharide gels, which highlights their dominant role in the mechanical architecture of marine gels. |
Databáze: | OpenAIRE |
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