Biomimetic Synthesis of Multilayered Aragonite Aggregates Using Alginate as Crystal Growth Modifier

Abstract

Polysaccharides were believed to play an important role in the mineralization process of many organisms. As the source of continuously and uniformly releasing alginate molecules and Ca(2+), alginate/Ca nanospherical gel was employed in the solution to induce the nucleation and growth of CaCO(3). Time-resolved transmission electron microscopy (TEM) was applied to study the crystallization at a very early stage. It was found that the initially formed lens-like vaterite particles gradually dissolved from the middle of the particle and released alginate molecules and Ca(2+) back into the system. As reaction time increased, the released substances were involved in the next stage of crystallization of CaCO(3), in the form of needle-like and shuttle-like aragonite particles sequentially depending on the concentration of alginate molecules and Ca(2+). "Egg-box" conformation of alginate and Ca(2+) was considered a skeleton for the growth of such aragonite particles. Notably, shuttle-like aragonite particles were composed of "bricks" of several hundred nanometers in size, which were very similar to biogenetic nacreous layers in shells.

Growth of Aragonite CaCO3 Whiskers in a Microreactor with Calcium Dodecyl Benzenesulfonate as a Control Agent

“…19,20,27 For example, alginate that forms one-dimensional framework could be used to promote the nucleation of CaCO 3 and lead to a controllable crystallization. 36 If the organic additives are uniformly dispersed in the system and dynamically adsorbed on the CaCO 3 surfaces, the organic chains will link with the whiskers on the side and keep the onedimensional growth, as shown in Figure 2, panel b. In the case of this condition, an efficient mixing process could also be achieved in this homogeneous reaction system.…”

Aragonite Nanorod Arrays through Molecular Controlled Growth on Single-Crystalline Substrate and Polysaccharide Surface

“…28−30 Particular watersoluble polymers, such as polysaccharides and amino acids, were reported to promote the growth of aragonite. 31,32 Thin aragonite films were formed on an insoluble organic polymer matrix, such as poly(vinyl alcohol) and chitosan, by the cooperative effects of poly(acrylic acid). 33 Aragonite nanorods were reported to be grown on calcite microcrystals with a positively charged polyelectrolyte (poly(allylamine hydrochloride).…”

Nucleation and Growth of Brushite in the Presence of Alginate

“…3 Polysaccharides are recognized as a strongly influential group of polymers acting upon calcium phosphate and calcium carbonate mineralization that are important classes of minerals in vertebrate and marine hard tissues, respectively. [5][6][7][8][9] Alginate is a linear polysaccharide copolymer, derived from brown sea algae and composed of 1-4 linked β-D-mannuronic acid (M) and α-Lguluronic acid (G) residues with an alternating or block structure. The M-and G-units of alginate differ in the orientation of carboxyl groups that in turn highly affects their functionalty.…”