Nanoscale Analysis of the Structure and Composition of Biogenic Calcite Reveals the Biomineral Growth Pattern.
ACS Nano
; 17(3): 2829-2839, 2023 02 14.
Article
em En
| MEDLINE
| ID: mdl-36696398
ABSTRACT
The vast majority of calcium carbonate biocrystals differ from inorganic crystals in that they display a patent nanoroughness consisting of lumps of crystalline material (calcite/aragonite) surrounded by amorphous pellicles. Scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS) was used to map the calcite secreted by a barnacle chemically and structurally with ultrahigh resolution (down to 1 nm). The material is composed of irregular lumps of calcite (up to two hundred nm in diameter) surrounded by relatively continuous cortexes (up to 20 nm thick) of amorphous calcium carbonate (ACC) and/or nanocalcite plus biomolecules, with a surplus of calcium relative to carbonate. We develop a model by which the separation of the crystalline and amorphous phases takes place upon crystallization of the calcite from a precursor ACC. The organic biomolecules are expelled from the crystal lattice and concentrate in the form of pellicles, where they stabilize minor amounts of ACC/nanocalcite. In this way, we change the previously established conception of biomineral structure and growth.
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Base de dados:
MEDLINE
Assunto principal:
Carbonato de Cálcio
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article