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Structure-property relationships of a biological mesocrystal in the adult sea urchin spine
Proceedings of the National Academy of Sciences, 109 (10): 3699--3704 (06.03.2012)
DOI: 10.1073/pnas.1109243109
Аннотация
Structuring over many length scales is a design strategy widely used in Nature to create materials with unique functional properties. We here present a comprehensive analysis of an adult sea urchin spine, and in revealing a complex, hierarchical structure, show how Nature fabricates a material which diffracts as a single crystal of calcite and yet fractures as a glassy material. Each spine comprises a highly oriented array of Mg-calcite nanocrystals in which amorphous regions and macromolecules are embedded. It is postulated that this mesocrystalline structure forms via the crystallization of a dense array of amorphous calcium carbonate (ACC) precursor particles. A residual surface layer of ACC and/or macromolecules remains around the nanoparticle units which creates the mesocrystal structure and contributes to the conchoidal fracture behavior. Nature's demonstration of how crystallization of an amorphous precursor phase can create a crystalline material with remarkable properties therefore provides inspiration for a novel approach to the design and synthesis of synthetic composite materials.
тэги
- biomineralization
- calcium-carbonate
- echinoderm-skeleton
- hierarchical-structuring
- mesocrystal
- skeletal-elements
