Organic and mineral networks in carapaces, bones and biomimetic materials

Skeletal tissues associate, in close interaction, an organic matrix and a mineral network. In crustaceans, chitin, the most frequent polysaccharide in invertebrate exoskeletons, is associated with calcite. In compact bone, collagen, major structural protein in vertebrate tissues is associated with hydroxyapatite. A parallel was evidenced in vivo between the three-dimensional assemblies of chitin and collagen matrices and molecular arrangements described in liquid crystals. The purified macromolecules, highly concentrated, assemble in vitro in ordered liquid crystalline phases. After stabilisation, they form biomimetic materials, presently investigated, in a pure state or in addition with inorganic phases to develop hybrid materials.