Microstructure and crystallographic-texture of giant barnacle (Austromegabalanus psittacus) shell.
J Struct Biol
; 156(2): 355-62, 2006 Nov.
Article
in En
| MEDLINE
| ID: mdl-16962792
ABSTRACT
Barnacle shell is a very complex and strong composite bioceramic composed of different structural units which consist of calcite 15 microcrystals of very uniform size. In the study reported herein, the microstructural organization of these units has been examinated in detail with optical and scanning electron microscopy, and X-ray diffraction techniques. These analyses showed that the external part of the shell has a massive microstructure consisting of randomly oriented crystals. Toward the interior, the shell became organized in mineral layers separated by thin organic sheets. Each of these mineral layers has a massive microstructure constituted by highly oriented calcite microcrystals with their c-axes aligned [(001) fibre texture] perpendicular to the organic sheets and the shell surface. Interestingly, in another structural unit, the shell shield, the orientation of the c-axis calcite crystals shifts from being perpendicular to being parallel to the shell surface across its thickness. This study provides evidence that the organic matrix is responsible for the organization of the shell mineral and exterts strong a strict control on the polymorphic type, size and orientation of shell-forming crystals.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thoracica
/
Crystallography
Limits:
Animals
Language:
En
Journal:
J Struct Biol
Journal subject:
BIOLOGIA MOLECULAR
Year:
2006
Document type:
Article
Affiliation country:
Spain