Superimposed effect of kinetics and echinoderm glycoproteins on hierarchical growth of calcium carbonate

We present here the synthesis of hierarchical calcite, grown in the presence of acidic glycoproteins isolated from adult spines of the sea urchin Evechinus chloroticus. Hierarchical growth is only achieved when kinetic growth control (attained for high concentrations of calcium ion) is superimposed on the thermodynamic constraints imposed by crystal growth under limiting carbon dioxide in the presence of glycoproteins. Cleaved oligosaccharides produce analogous hierarchical structures, suggesting that they provide a similar growth environment for the calcium carbonate as the parent glycoproteins. Their effect is achieved at lower concentration as compared with the glycoproteins. Deglycosylated protein does not produce this effect and at high concentrations completely inhibits calcium carbonate growth.