Design strategies in mineralized biological materials

Organisms have been producing mineralized skeletons for the past 550 million years. They have evolved many different strategies for improving these materials at almost all hierarchical levels from Ångstroms to millimetres. Key components of biological materials are the macromolecules, which are intimately involved in controlling nucleation, growth, shaping and adapting mechanical properties of the mineral phase to function. One interesting tendency that we have noted is that organisms have developed several strategies to produce materials that have more isotropic properties. Much can still be learned from studying the principles of structure–function relations of biological materials. Some of this information may also provide new ideas for improved design of synthetic materials.