Polymorphism and architectural crystal assembly of calcium carbonate in biologically inspired polymeric matrices

The control of the polymorphism and architectural crystal assembly of calcium carbonate minerals in gels formed by means of collagenous matrices with entrapped polypeptides is reported. It has been observed that the calcium carbonate polymorphic selectivity is related to the local supersaturation within the microenvironment where nucleation and growth occur. This crucial parameter is controlled in terms of the entrapped additive concentration and of the tailoring of the biopolymeric scaffold by mechanical deformation. Specific orientation effects and crystal aggregation of the mineral phases can be controlled either by the charged polypeptide with a beta structure or by the structural organization of the triple helical stretches in the collagenous matrix. This results in the growth and assembly of crystals into desired shapes and sizes by molecular recognition at a definite crystal face or by the control of the organic macromolecular microenvironment fit in the emerging area of biologically inspired approach to structured inorganic materials with appropriate physical and chemical properties.