Artículos de revistas
Microstructure and crystallographic-texture of giant barnacle (Austromegabalanus psittacus) shell
Fecha
2006-11Registro en:
Journal of Structural Biology Volume: 156 Issue: 2 Pages: 355-362
DOI: 10.1016/j.jsb.2006.04.009
Autor
Rodríguez Navarro, Alejandro B.
CabraldeMelo, Christiane
Batista, Nelson
Morimoto, Nilton
Álvarez Lloret, Pedro
Ortega Huertas, Miguel
Fuenzalida, Víctor M.
Wiff, Juan P.
Arias, José Luis
Institución
Resumen
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.