Shape-preserving amorphous-to-crystalline transformation of CaCO₃ revealed by in situ TEM.

ABSTRACT: Organisms use inorganic ions and macromolecules to regulate crystallization from amorphous precursors, endowing natural biominerals with complex morphologies and enhanced properties. The mechanisms by which modifiers enable these shape-preserving transformations are poorly understood. We used in situ liquid-phase transmission electron microscopy to follow the evolution from amorphous calcium carbonate to calcite in the presence of additives. A combination of contrast analysis and infrared spectroscopy shows that Mg ions, which are widely present in seawater and biological fluids, alter the transformation pathway in a concentration-dependent manner. The ions bring excess (structural) water into the amorphous bulk so that a direct transformation is triggered by dehydration in the absence of

SUBMITTER: Liu Z 

PROVIDER: S-EPMC7035502 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature