Biomineralized tissues, mechanical

Mechanical Design of Biomineralized Tissues. Bone and Other Hierarchical Materials... 

Bone and teeth in mammals and bony fishes all rely on calcium phosphates in the form of hydroxyapatite [Ca5(P04)30H]2, usually associated with around 5% carbonate (and referred to as carbonated apatite). The bones of the endoskeleton and the dentin and enamel of teeth have a high mineral content of carbonated apatite, and represent an extraordinary variety of structures with physical and mechanical properties exquisitely adapted to their particular function in the tissue where they are produced. We begin by discussing the formation of bone and then examine the biomineralization process leading to the hardest mineralized tissue known, the enamel of mammalian teeth. 

Looking at the literature in the field of biomineralization, one notices, that the majority of articles is descriptive in nature. On the basis of electron micrographs or thin section studies, the intricate relationships between mineral phase and organic matrix are investigated. Other papers deal with the chemical composition of the mineralized tissue and the minerals. Only a few authors address themselves to the question of metal ion transport mechanisms in cellular systems and the solid state principles involved in mineral deposition on organic substrates. All three sets of information, however, are essential to understand calcification processes. It appears, therefore, that information on the functionality of metal ions in living systems and their role in mineral deposition are particularly desired in this area of research. 

In addition to the molecular localization of apatite in vertebrate tissues, we hasten to point out that the quest to understand and control, or at least modulate, the mechanisms of bone biomineralization with its many facets and levels of mineral deposition continue. The intricate... 

Biomineralization strategies and the biominerals are, for many good reasons, important to all who inhabit the Earth. The crossovers between the biomineralizers, the chemistry and the morphology of the minerals, the tissue textures, the cells, and the mechanisms that characterize some life forms offer intriguing insights to the physical-chemical laws of nature. 

Zhang Q, Mochalin VN, Neitzel 1, Hazeli K, Niu J, Kontsos A, et al. Mechanical properties and biomineralization of multifunctional nanodiamond-PLLA composites for bone tissue engineering. Biomaterials 2012 33 5067-75. 

In this book Song et al (10) described a novel nucleation and mineral growth process to produce a bone-like biomineral con site. The crosslinked gelatin-chitosan blend made by Payne et al fi/J may perhaps be used as biomimetic soft tissue or for bioencapsulation. The sorbitol-based polyesters synthesized by Mei at al (27) and Kulshrestha et al (26) may possibly find applications in tissue engineering. Biswas et al (13) described the preparation and the mechanical properties of modified zein. Fishman et al (12) made pectin-starch and pectin-poly(vinyl alcohol) blends and found them to be strong, flexible films. 

Because of its obvious importance to biology, medicine, and dentistry, the mechanism of biomineralization has been the subject of much research (2-4), This cannot be adequately reviewed here and only a simplified model is presented as background. Hard tissue formation begins with deposition of structural biopolymers. 

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