Artículo de revista
pH-Dependent Schemes of Calcium Carbonate Formation in the Presence of Alginates
Fecha
2016Registro en:
Cryst. Growth Des. 2016, 16, 1349−1359
DOI: 10.1021/acs.cgd.5b01488
Autor
Rao, Ashit
Fernández, María S.
Berg, John K.
Sánchez, Marianela
Drechsler, Markus
Neira Carrillo, Andrónico
Arias Bautista, José
Gebauer, Denis
Coelfen, Helmut
Institución
Resumen
From recent studies on bone and shell formation, the importance of polysaccharides in biomineralization processes is gradually being recognized. Through ion-complexation and self-assembly properties, such macromolecules have remarkable effects on mineralization. However, their influences on the different regimes of crystallization including the interactions with precursor species are unclear. The present study therefore addresses calcium carbonate mineralization in the presence of alginates, a class of linear copolymeric saccharides composed of beta-1,4 linked D-mannuronic and L-guluronic acid. During mineralization, this biopolymer is found to exert pH-dependent control over mineralization pathways in terms of the stability of prenucleation dusters, inhibitory effect toward nucleation and initially formed postnucleation products. Remarkably in the presence of this macromolecular additive; either amorphous or crystalline vaterite particles can be selectively nucleated in a pH-dependent manner. This is validated by electron microscopy wherein vaterite particles are intimately associated with alginate assemblies after nucleation at pH 9.75. At lower pH, aggregates, of amorphous particles are formed. Thus, in addition to the general focus on biochemical properties of additives, solution pH, a physiologically fundamental parameter significantly alters the scheme of mineralization.