title: Structure-property relationships of a biological mesocrystal in the adult sea urchin spine.
abstract: 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.
authors.affiliation: Max-Planck-Institute of Colloids and Interfaces, Research Campus Golm, Am Mühlenberg 1, D-14424 Potsdam, Germany.
authors.forename: Jong
authors.initials: J
authors.lastname: Seto
authors.forename: Yurong
authors.initials: Y
authors.lastname: Ma
authors.forename: Sean A
authors.initials: SA
authors.lastname: Davis
authors.forename: Fiona
authors.initials: F
authors.lastname: Meldrum
authors.forename: Aurelien
authors.initials: A
authors.lastname: Gourrier
authors.forename: Yi-Yeoun
authors.initials: YY
authors.lastname: Kim
authors.forename: Uwe
authors.initials: U
authors.lastname: Schilde
authors.forename: Michael
authors.initials: M
authors.lastname: Sztucki
authors.forename: Manfred
authors.initials: M
authors.lastname: Burghammer
authors.forename: Sergey
authors.initials: S
authors.lastname: Maltsev
authors.forename: Christian
authors.initials: C
authors.lastname: Jäger
authors.forename: Helmut
authors.initials: H
authors.lastname: Cölfen
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008274:Magnesium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D012617:Sea Urchins / Q000502:physiology*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013329:Structure-Activity Relationship; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D046911:Macromolecular Substances; D002119:Calcium Carbonate; D008274:Magnesium