Learning from Nature How to Design Biomimetic Calcium-Phosphate Coatings

Mineralized biosystems can gather unique extraordinary properties that most of the times have a complexity beyond our knowledge. However, their formation follows general common principles across different species. In contrast to colloidal or solution processing techniques commonly used for the production of synthetic minerals or their precursors, biomineral production occurs under moderate conditions of supersaturation [1]. For biomineralization to occur specific subunit compartments or microenvironments need to be created, in order to stimulate crystal formation at certain “functional sites” and inhibition or prevention of the process at all other sites [1-3]. The highly specific control of morphology, location, orientation and crystallographic phase all indicate the existence of an optimized or “engineered” substrate surface. The key characteristics of these optimized interfaces are a mystery at present, namely because of the complexity of most biological model systems. Investigations of representative systems, such as nacre [4,5], dentin [6,7], enamel [8-10], cartilage [11,12] and bone [1315], highlight the definite importance of the microenvironments and of the orientation between the organic matrix and the precursors for the mineral formation. At the macroscopic level the growth of a biomineralized structure gains shape by the sequential packaging of units together, resulting in unique composite structures that are prepared to accommodate later stages of the organism growth and repair [16]. The sophistication of nature’s “bottom-up” approach for the production of complex but yet functional structures has inspired a great number of researchers in order to fabricate enhanced materials. However, to achieve Nature’s efficacy on solving its problems is still a utopia. Nevertheless, the richness of information that is stored in each biomineralized tissue has been a source of new ideas over different fields like chemistry