Obtainment of Spherical-Shaped Calcite Crystals Induced by Intramineral Proteins Isolated from Eggshells of Ostrich and Emu

In this work, we have performed a set of experiments to study how intramineral proteins affected the growth of calcite crystals and induced spherical growth. Intramineral proteins were first isolated from ostrich and emu eggshells and then purified by liquid chromatography. Samples of these proteins were analyzed by means of cyclic voltammetry to check their selectivity for carbonate ions. Then they underwent assays in solution through dynamic light scattering (DLS) to help us establish their homogeneity and stability (whether individually or in pairs) in the presence of carbonate ions. This was followed by in vitro crystallization experiments to determine how they affected the morphology of calcite crystals interacting with the intramineral proteins. Finally, scanning electron microscopy (SEM) showed that the morphology of the calcite crystals was strongly modified in the presence of these intramineral proteins.