Nucleation and Growth of CaCO3 Mediated by the Egg-White Protein Ovalbumin: A Time-Resolved in situ Study Using Small-Angle Neutron Scattering
Citations Over TimeTop 10% of 2008 papers
Abstract
Mineralization of calcium carbonate in aqueous solutions starting from its initiation was studied by time-resolved small-angle neutron scattering (SANS). SANS revealed that homogeneous crystallization of CaCO 3 involves an initial formation of thin plate-shaped nuclei which subsequently reassemble to 3-dimensional particles, first of fractal and finally of compact structure. The presence of the egg-white protein ovalbumin leads to a different progression of mineralization through several stages; the first step represents amorphous CaCO 3, whereas the other phases are crystalline. The formation and dissolution of the amorphous phase is accompanied by Ca (2+)-mediated unfolding and cross-linking of about 50 protein monomers showing the characteristic scattering of linear chains with a large statistical segment length. The protein complexes act as nucleation centers for the amorphous phase because of their enrichment by Ca (2+) ions. SANS revealed the sequential formation of CaCO 3 starting from the amorphous phase and the subsequent formation of the crystalline polymorphs vaterite and aragonite. This formation from less dense to more dense polymorphs follows the Ostwald-Volmer rule.
Related Papers
- → Calcium Carbonate Crystal Forms Formed from Sea Water by Inorganic Processes(1962)83 cited
- → Studies on the formation of calcified egg-capsules of ampullarid snails(1974)32 cited
- → Controls of Polymorphism and Morphology of Calcium Carbonate Compounds Formed by Crystallizing Amorphous Calcium Carbonate Hydrate(1994)31 cited
- → Chemical and crystallographic studies on 33 cases of calcium carbonate gallstone (so-called limy bile)(1986)14 cited
- Growth of Calcium Carbonate Crystal in Gels(2006)