Control Over Aragonite Crystal Nucleation and Growth: An In Vitro Study of Biomineralization

Control over calcium carbonate deposition in an in vitro system containing the major macromolecular components present in mollusk shell is shown to depend on the presence of a specific protein fraction in the appropriate microenvironment, in this case, silk fibroin adsorbed on β-chitin. Experiments with synthetic polypeptides elucidate aspects of the sequence dependency of nucleation of the aragonite polymorph, shown here growing in the nacreous layer of the bivalve Atrina serrata (note the orientation of the small, newly formed crystals and their merging together in more mature areas).