Strong stabilization of amorphous calcium carbonate emulsion by ovalbumin: gaining insight into the mechanism of 'polymer-induced liquid precursor' processes. - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Journal of the American Chemical Society Année : 2011

Strong stabilization of amorphous calcium carbonate emulsion by ovalbumin: gaining insight into the mechanism of 'polymer-induced liquid precursor' processes.

Résumé

The impact of the ovo proteins ovalbumin and lysozyme-present in the first stage of egg shell formation-on the homogeneous formation of the liquid amorphous calcium carbonate (LACC) precursor, was studied by a combination of complementing methods: in situ WAXS, SANS, XANES, TEM, and immunogold labeling. Lysozyme (pI = 9.3) destabilizes the LACC emulsion whereas the glycoprotein ovalbumin (pI = 4.7) extends the lifespan of the emulsified state remarkably. In the light of the presented data: (a) Ovalbumin is shown to behave commensurable to the 'polymer-induced liquid precursor' (PILP) process proposed by Gower et al. Ovalbumin can be assumed to take a key role during eggshell formation where it serves as an effective stabilization agent for transient precursors and prevents undirected mineralization of the eggshell. (b) It is further shown that the emulsified LACC carries a negative surface charge and is electrostatically stabilized. (c) We propose that the liquid amorphous calcium carbonate is affected by polymers by depletion stabilization and de-emulsification rather than 'induced' by acidic proteins and polymers during a so-called polymer-induced liquid-precursor process. The original PILP coating effect, first reported by Gower et al., appears to be a result of a de-emulsification process of a stabilized LACC phase. The behavior of the liquid amorphous carbonate phase and the polymer-induced liquid-precursor phase itself can be well described by colloid chemical terms: electrostatic and depletion stabilization and de-emulsification by depletion destabilization.

Domaines

Biomatériaux

Dates et versions

hal-00614962 , version 1 (17-08-2011)

Identifiants

Citer

Stephan E. Wolf, Jork Leiterer, Vitaliy Pipich, Raul Barrea, Franziska Emmerling, et al.. Strong stabilization of amorphous calcium carbonate emulsion by ovalbumin: gaining insight into the mechanism of 'polymer-induced liquid precursor' processes.. Journal of the American Chemical Society, 2011, 133 (32), pp.12642-12649. ⟨10.1021/ja202622g⟩. ⟨hal-00614962⟩
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