TY - JOUR

T1 - pH-Dependent Schemes of Calcium Carbonate Formation in the Presence of Alginates

AU - Rao, Ashit

AU - Vasquez-Quitral, Patricio

AU - Fernandez, Maria S.

AU - Berg, John K.

AU - Sanchez, Marianela

AU - Drechsler, Markus

AU - Neira-Carrillo, Andronico

AU - Arias, Jose L.

AU - Gebauer, Denis

AU - Coelfen, Helmut

N1 - Funding information: This work was supported by Projects FONDECYT 1120172 and 1140660, granted by the Chilean Council for Science and Technology (CONICYT), and Project PCCI12-039 CONICYT/DAAD and PCCI12-038 CONICYT/MinCyt. A.N.C. is grateful for funding by Program U-Redes, Vice-presidency of Research and Development, University of Chile. P.V.-Q. acknowledges a fellowship provided by CONICYT and German Academic Exchange Service (DAAD). The authors acknowledge the funding by DAAD from the ALECHILE program for 2013/2014. A.R. acknowledges a fellowship from Konstanz Research School Chemical Biology. D.G. is a Research Fellow of the Zukunftskolleg of the University of Konstanz. We thank Dr. Roland Kröger, Department of Physics, University of York, UK, for his expert advice on analyses of electron microscopy data.

PY - 2016

Y1 - 2016

N2 - 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 β-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 clusters, 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.

AB - 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 β-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 clusters, 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.

UR - http://www.scopus.com/inward/record.url?scp=84960158284&partnerID=8YFLogxK

U2 - 10.1021/acs.cgd.5b01488

DO - 10.1021/acs.cgd.5b01488

M3 - Article

VL - 16

SP - 1349

EP - 1359

JO - Crystal growth & design

JF - Crystal growth & design

SN - 1528-7483

IS - 3

ER -