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The biological mediation of mineral formation (biomineralization) is realized through diverse organic macromolecules that guide this process in a spatial and temporal manner. Although the role of these molecules in biomineralization is being gradually revealed, the molecular basis of their regulatory function is still poorly understood. In this study, the incorporation and distribution of the model intrinsically disordered starmaker‐like (Stm‐l) protein, which is active in fish otoliths biomineralization, within calcium carbonate crystals, is revealed. Stm‐l promotes crystal nucleation and anisotropic tailoring of crystal morphology. Intracrystalline incorporation of Stm‐l protein unexpectedly results in shrinkage (and not expansion, as commonly described in biomineral and bioinspired crystals) of the crystal lattice volume, which is described herein, for the first time, for bioinspired mineralization. A ring pattern was observed in crystals grown for 48 h; this was composed of a protein‐enriched region flanked by protein‐depleted regions. It can be explained as a result of the Ostwald‐like ripening process and intrinsic properties of Stm‐l, and bears some analogy to the daily growth layers of the otolith. [ABSTRACT FROM AUTHOR]

The article presents the synchrotron microstructure study on bio-inspired engineering of a zinc oxide (ZnO)/amino acid composite to improve control of the band-gap value of ZnO as a semiconductor. Also cited are the properties of materials produced by organisms like their unique crystal shapes and high fracture resistance, as well as the lattice distorion and band-gap alteration of ZnO semiconductor.

Biominerals exhibit morphologies, hierarchical ordering and properties that invariably surpass those of their synthetic counterparts. A key feature of these materials, which sets them apart from synthetic crystals, is their nanocomposite structure, which derives from intimate association of organic molecules with the mineral host. We here demonstrate the production of artificial biominerals where single crystals of calcite occlude a remarkable 13?wt% of 20?nm anionic diblock copolymer micelles, which act as 'pseudo-proteins'. The synthetic crystals exhibit analogous texture and defect structures to biogenic calcite crystals and are harder than pure calcite. Further, the micelles are specifically adsorbed on {104} faces and undergo a change in shape on incorporation within the crystal lattice. This system provides a unique model for understanding biomineral formation, giving insight into both the mechanism of occlusion of biomacromolecules within single crystals, and the relationship between the macroscopic mechanical properties of a crystal and its microscopic structure. [ABSTRACT FROM AUTHOR]

The synthetic formation of mercury thiolates has been known for almost 200 years. These compounds are usually formed by a slow reaction of mercury salts with thiolates or disulfides to produce small (up to 1 μm), plate-like crystals of Hg(S-R)2. Herein we show that such mercury thiolates can be formed directly from liquid mercury via sonication with neat thiols. The process not only produces crystals very rapidly (within seconds) but also leads to the formation of large crystals (up to hundreds of micrometers). The high quality of these crystals enabled their detailed structural characterization, which showed that the crystals are composed of ordered Hg(thiol)2 stacks. We extended the experimental procedure to form and characterize a range of Hg thiolate crystals with various chain lengths. We propose a new self-assembly mechanism that can explain how sonication-which is usually used to break chemical bonds, to disperse materials, and to form nanosized crystallites-may lead to the growth of large, high-quality crystals. [ABSTRACT FROM AUTHOR]

Of the model intrinsically disordered Starmaker-like (Stm-l) protein, which is active in fish otoliths biomineralization, within calcium carbonate crystals was studied in vitro. Of the model intrinsically disordered Starmaker-like (Stm-l) protein, which is active in fish otoliths biomineralization, within calcium carbonate crystals was studied in vitro. The Stm-l promotes calcium carbonate nucleation and anisotropic tailoring of crystal morphology. [Extracted from the article]

Composite biogenic materials produced by organisms have a complicated design on a nanometre scale. An outstanding example of organic–inorganic composites is provided by mollusc seashells, whose superior mechanical properties are due to their multi-level crystalline hierarchy and the presence of a small amount (0.1–5 wt%) of organic molecules. The presence of organic molecules, among other characteristics, can influence the coherence length for X-ray scattering in biogenic crystals. Here we show the results of synchrotron high-resolution X-ray powder diffraction measurements in biogenic and non-biogenic (geological) aragonite crystals. On applying the Rietveld refinement procedure to the high-resolution diffraction spectra, we were able to extract the aragonite lattice parameters with an accuracy of 10 p.p.m. As a result, we found anisotropic lattice distortions in biogenic aragonite relative to the geological sample, maximum distortion being 0.1% along the c axis of the orthorhombic unit cell. The organic molecules could be a source of these structural distortions in biogenic crystals. This finding may be important to the general understanding of the biomineralization process and the development of bio-inspired 'smart' materials. [ABSTRACT FROM AUTHOR]

As one of the most abundant materials in the world, calcium carbonate, CaCO3, is the main constituent of the skeletons and shells of various marine organisms. It is used in the cement industry and plays a crucial role in the global carbon cycle and formation of sedimentary rocks. For more than a century, only three polymorphs of pure CaCO3—calcite, aragonite, and vaterite—were known to exist at ambient conditions, as well as two hydrated crystal phases, monohydrocalcite (CaCO3·1H2O) and ikaite (CaCO3·6H2O). While investigating the role of magnesium ions in crystallization pathways of amorphous calcium carbonate, we unexpectedly discovered an unknown crystalline phase, hemihydrate CaCO3·½H2O, with monoclinic structure. This discovery may have important implications in biomineralization, geology, and industrial processes based on hydration of CaCO3. [ABSTRACT FROM AUTHOR]