Morphologies and growth model of biomimetic fabricated calcite crystals using amino acids and insoluble matrix membranes of Mytilus edulis

Protein membranes extracted from mollusk shells were selected as substrates to precipitate calcium carbonate crystals in CaCl2 solutions containing glycine or aspartic acid. This research mainly concentrated on the morphologies of the synthesized calcite particles rather than on the control over the polymorphs. The amino acids might restrict the growth of the negative directions of the calcite's {104} faces. Aspartic acid might serve as an agglutinant of several crystals. Compared with the silicon substrate results, protein membranes of the nacreous layer have obvious inductivity of nucleation through interfacial matching to the (001) faces of calcite crystals, and in the presence of glycine we also observed some mushroom-like particles. Their nucleation orientation and formation mechanism were represented by schematics. On the other hand, protein membranes of the prismatic layer did not have similar functions. These works are in vitro studies of biomineralization.