Biomineralization crystals

Fricke M, Volkmer D (2007) Crystallization of Calcium Carbonate Beneath Insoluble Mono-layers Suitable Models of Mineral-Matrix Interactions in Biomineralization 270 1-41 Fujimoto D, see Tamura R (2007) 269 53-82... 

The bones and teeth of humans and other vertebrate animals, for example, consist mainly of a composite material made up of an organic substance, collagen, and a biomineral, calcium carbonate phosphate (see Textboxes 32 and 61). The latter, which makes up about two-thirds of the total dry weight of bone, is composed of calcium phosphate containing between 4-6% calcite (composed of calcium carbonate) as well as small amounts of sodium, magnesium, fluorine, and other trace elements. The formula Ca HPChXPChMCChXOH) approximately represents its composition its crystal structure is akin to that... 

Mann, S., Archibald, D.D., Didymus, J. M., Douglas, T., Heywood, B.R., Meldrum, F.C. and Reeves, N.J. (1993) Crystallization at inorganic-organic interfaces-Biominerals and biomimetic synthesis. Science, 261, 1286-1292. 

The formation of the solid phase (nucleation, precipitation, crystal growth, biomineralization) ... 

The most important organic components of bone are collagens (mainly type 1 see p.344) and proteoglycans (see p. 346). These form the extracellular matrix into which the apatite crystals are deposited (biomineralization). Various proteins are involved in this not yet fully understood process of bone formation, including collagens and phosphatases. Alkaline phosphatase is found in osteoblasts and add phosphatase in osteoclasts. Both of these enzymes serve as marker enzymes for bone cells. 

SOLUTION BEHAVIOR. Biomineralization is dominated by physical chemical considerations , and we begin with a discussion of real electrolyte solutions in which the concentration of a substance exceeds its thermodynamically defined solubility. In such a case, the presence of a coexisting crystal surface will lead to crystal growth. 

Once formed, crystals can interact with or adhere to other components. Adhesion can occur directly between crystals to form larger structures which may act as the nidus for further mineralization. Crystals can also interact with metabolites and/or tissues to form such structures. These interactions can and do alter the stereochemical course of crystal assembly, and molecular recognition probably accounts for the striations and intricate geometries adopted by biomineralized structures. The role and composition of metabolites comprising the matrix may be useful to understanding the local and large-scale structure of biominerals. 

The ratio of the instantaneous solute concentration c to the solute s solubility s, where the latter is the solute concentration in equihbrium with its crystalline or precipitated phase. Hence, RS = c/s, and a supersaturated solution experiences a thermodynamic driving force (AG = RT ln[RS]). A supersaturated solution will remain as a metastable state, because crystallization or precipitation requires a mechanism for relieving the supersaturated condition (eg., nucleation or addition of crystallite/precipitate). See Biomineralization... 

Banfield J.F., Welch S.A., Zhang H., Ebert T.T., and Penn R.L. (2000) Aggregation-based crystal growth and microstructure development in natural iron oxyhydroxie biomineralization products. Science 289, 751-754. 

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