Multiscale structure of sheet nacre

Biomaterials. 2005 Nov;26(31):6254-62. doi: 10.1016/j.biomaterials.2005.03.028.

Abstract

This work was conducted on Pinctada maxima nacre (mother of pearl) in order to understand its multiscale ordering and the role of the organic matrix in its structure. Intermittent-contact atomic force microscopy with phase detection imaging reveals a nanostructure within the tablet. A continuous organic framework divides each tablet into nanograins. Their shape is supposed to be flat with a mean extension of 45nm. TEM performed in the darkfield mode evidences that at least part of the intracrystalline matrix is crystallized and responds like a 'single crystal'. The tablet is a 'hybrid composite'. The organic matrix is continuous. The mineral phase is thus finely divided still behaving as a single crystal. It is proposed that each tablet results from the coherent aggregation of nanograins keeping strictly the same crystallographic orientation thanks to a hetero-epitaxy mechanism. Finally, high-resolution TEM performed on bridges from one tablet to the next, in the overlying row, did not permit to evidence a mineral lattice but crystallized organic bridges. The same organic bridges were evidenced by SEM in the interlaminar sequence.

Publication types

  • Evaluation Study

MeSH terms

  • Animals
  • Biocompatible Materials / analysis*
  • Biocompatible Materials / chemistry*
  • Crystallization / methods*
  • Macromolecular Substances / analysis
  • Macromolecular Substances / chemistry
  • Materials Testing
  • Molecular Conformation
  • Mollusca / chemistry*
  • Nanostructures / analysis
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Surface Properties
  • Tissue Extracts / analysis*
  • Tissue Extracts / chemistry*

Substances

  • Biocompatible Materials
  • Macromolecular Substances
  • Tissue Extracts