Oriented Crystallization of Vaterite in Collagenous Matrices

Abstract

The influence of high supersaturation on kinetic control and the importance of the polypeptide structure in the crystallization of calcium carbonate polymorphs were studied in crosslinked gelatin films containing high concentrations of the polypeptides poly-l-aspartate and poly-l-glutamate. Oriented crystallization of vaterite occurs in uniaxially deformed gelatin films containing poly-l-aspartate at concentations greater than 100 mg per gram of gelatin. The fact that no orientation of the mineral phase was observed with entrapped poly-l-glutamate at the same concentrations suggests that the oriented crystallization is controlled by the b sheet structure assumed by poly-l-aspartate in the presence of calcium ions. These results indicate that local supersaturation in the microenvironment in which nucleation and growth occur plays an important role in controlling the deposition of vaterite in cross-linked gelatin films. However, collagen bundles and the ordered and oriented polypeptide chains of poly-l-aspartate can contribute to the control of polymorphism by inducing the formation of a specific phase by epitaxial crystallization, as suggested by the preferentially oriented deposition of vaterite and aragonite. This is of potential significance in biomineralization processes and in materials science.

Effect of Nanoscale Confinement on the Crystallization of Potassium Ferrocyanide

“…As an alternative to additive-directed crystallization, it is also becoming increasingly evident that the micro-environments in which crystals form can themselves define crystallization pathways and products. [15][16][17][18][19] Not only is this of particular importance to processes that naturally occur in confinement such as weathering, biomineralization and the manufacture of nanomaterials, but confinement can potentially provide a stand-alone means of controlling crystallization.…”

Is the contribution of bacteria to terrestrial carbon budget greatly underestimated?

“…The influence of organic matter, exopolysaccharides and polyaspartate in the precipitation of vaterite can also be found in nature (Falini et al 1998;Gower and Tirrell 1998). Vaterite crystals similar to those obtained in this study have recently been found in Lake Issyk-Kul (Kyrgyzstan) and have been attributed to Synechococcus activity in mucilagenous mats containing polyaspartate (Giralt et al 2001).…”

Crystal Growth Mechanism of Vaterite in the Systems Containing Charged Synthetic Poly(Amino Acids)

“…[8] A considerable amount of research on the processes occurring at the organic-inorganic interfaces and of calcium carbonates, related to the biomineralization or bioinorganic chemistry, has already been performed. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] Thus, the model studies on crystallization at the organic-inorganic interfaces, carried out in vitro, typically use the macromolecules extracted from biogenic crystals [15,[17][18][19][21][22][23][24][25][26][27][28][29][30] or synthetic macromolecules, [9,14,15,[31][32][33][34][35][36] which are considered to be their analogues. In addition, the experimental data indicate that the metastable modifications like ACC, are the first mineral phases that appear during the formation of shells, thus acting as a reservoir of constituting ions for subsequent formation of stable modifications.…”