Use of biopolymers as oriented supports for the stabilization of different polymorphs of biomineralized calcium carbonate with complex shape

This work concerns the use of different biopolymers such as chitosan, alginate or κ-carrageenan as substrates to contribute to the study of the crystallization of calcium carbonate. The experimental biomimetic approach involves the preparation of mixtures of biopolymer solutions with a solution of CaCl2, which is processed by means of spin-coating and then exposed to CO2 by a slow diffusion method for the growth of CaCO3. The obtained crystals show that each biopolymer has different effects on the crystallization habit. Different agglomerations of calcium carbonate crystals are initially the vaterite phase, which is subsequently stabilized as calcite. Biomineralization on each biopolymer gave rise to complex structures very different to those normally found in vitro, but similar to those observed in Nature. This confirms the strong influence of the macromolecules with ionizable groups on the stabilization of a determined polymorph and also on the morphology of the calcium carbonate crystals.