Chemical Heterogeneities within the Disordered Mineral domains of Aragonite Platelets in nacre from the European Abalone Haliotis tuberculata - Sorbonne Université Access content directly
Journal Articles Journal of Physical Chemistry C Year : 2020

Chemical Heterogeneities within the Disordered Mineral domains of Aragonite Platelets in nacre from the European Abalone Haliotis tuberculata

Abstract

Since the observation in 2005 of a disordered mineral layer at the surface of aragonite platelets in abalone Haliotis laevigata nacre, the model of the organo–mineral interface in such biomineralized tissue has been challenged. As a direct interaction between the aragonite crystalline core and the organic matrix is no longer appropriate to describe such interface, a structural description of the disordered mineral domains at the atomic level is a key for a comprehensive view of nacre ultrastructure. Here, we use European abalone Haliotis tuberculata as a model to investigate aragonite nacre through high-resolution transmission electron microscopy (HR-TEM) and multinuclear solid state nuclear magnetic resonance (ssNMR). The presence of a disordered domain around aragonite crystals is shown through HR-TEM observations similarly to H. laevigata. The structure and the ionic composition of the disordered mineral environments of H. tuberculata nacre are investigated through 1H, 13C, 43Ca, and 23Na ssNMR. Interestingly, we demonstrate that the disordered mineral domains in nacre seem to be heterogeneous in terms of structure and chemical composition and do not match with amorphous calcium carbonate stricto sensu. At least three different carbonates species are evidenced, including CO32– and HCO3– present in the same mineral domain and closely associated with rigid H2O molecules. The local disorder around these ions is found to be inhomogeneous as some CO32– possess an aragonitic environment and are rather ordered (according to the position and line width of their 13C resonance) whereas, in opposition, the chemical environment around HCO3– is highly distributed. The analysis of potential cations as counterions revealed the presence of disordered Ca2+ and the presence of Na+ closely associated with HCO3–. On the basis of these structural data, we propose an atomic-level model for the disordered domains in abalone (H.tuberculata) nacre where the protonation level of carbonate ions, the proportion of sodium ions and the local disorder are increasing from the inner to the outer part of disordered domains. These results give an unprecedented structural view at the atomic scale of such disordered mineral domains in nacre aragonite tablets.
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Dates and versions

hal-03013898 , version 1 (19-11-2020)

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Cite

Widad Ajili, Guillaume Laurent, Nicolas F Menguy, Axel Gansmuller, Sylvain Huchette, et al.. Chemical Heterogeneities within the Disordered Mineral domains of Aragonite Platelets in nacre from the European Abalone Haliotis tuberculata. Journal of Physical Chemistry C, 2020, 124 (26), pp.14118-14130. ⟨10.1021/acs.jpcc.0c00280⟩. ⟨hal-03013898⟩
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