Biomineralization strategies

Assembly and mineralization processes in biomineralization strategies for forming biological composite materials... 

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. 

The most recent and most ambitious examples of integration of biomineralization strategies into biotechnologically relevant applications concern materials where whole living cells have been encapsulated. Although few examples have made it into commercial products, some examples are worth mentioning. Encapsulating whole cells in biomineral porous matrices allows the... 

As mentioned earlier, biological systems have developed optimized strategies to design materials with elaborate nanostructures [6]. A straightforward approach to obtaining nanoparticles with controlled size and organization should therefore rely on so-called biomimetic syntheses where one aims to reproduce in vitro the natural processes of biomineralization. In this context, a first possibility is to extract and analyze the biological (macro)-molecules that are involved in these processes and to use them as templates for the formation of the same materials. Such an approach has been widely developed for calcium carbonate biomimetic synthesis [13]. In the case of oxide nanomaterials, the most studied system so far is the silica shell formed by diatoms [14]. 

However, when compared to the striking achievements of biomineralizing systems, in vitro macromolecular-based strategies still exhibit some limitations. First,... 

Biomineralization is a slow and complicated in vivo process. Many simple in vitro systems have been developed to model a particular aspect of the biomineralization process. Although in most cases the biological relevance of the in vitro systems may require further justification, the results can provide important insights into the processes being mimicked. In the near future, this divide-and-conquer approach will remain the most effective strategy for the study of biomineralization. 

The chiton tooth, dentin and the sea urchin larval spicule reflect the enormous diversity of the field of biomineralization. They differ with respect to the nature of their mineral and macromolecular components, as well as their structures. Few underlying common strategies can be recognized the delineation of a dedicated space in which the mineralized tissue forms, the formation of mineral in a preformed framework within this space, and the precipitation of mineral from a supersaturated phase. In this section we will reexamine some of these underlying issues, focussing in particular on the microenvironment in which mineralization occurs. 

The importance of the survival of land-based communities on plants suggested that our purview must include plant biomineralization, the materials, mechanisms, and strategies. For our summary we ask why biominerahze and olfer a few suggestions based predominantly on plant researches. The reasons for biomineralization we have outlined are appropriate to other mineral-producing life forms, and have often been discussed. However, in the process of reviewing the evolutionary development, some novel approaches, if not answers, to this basic question are preferred. 

As we begin to unravel the mechanisms by which biominerals are produced, more recently efforts have been directed to replicating key fabrication strategies and structural features into materials design. In this introductory section, we present a brief account of the principles involved in the formation of biominerals or if you prefer, the mles of thumb which govern the deposition of solid-state inorganic material. 

The natural world synthesizes a lot of polymers and composites at different scales, providing valuable principles and insights for the fabrication of nanopoiymers and nanocomposites. Here, two important biological synthesis strategies, biomineralization and synthetic biology, are introduced. 

Figure 4.1 Synthesis of bone-like composites through a biomimetic strategy inspired from bone biomineralization, (a) Biomimetic composites were obtained by first cross-linking maleic chitosan with PEGDA under UV light in water to form 3-D hydrogel networks, followed by biomimetic mineralization Images of maleic chitosan/PEGDA hydrogel (b) before and (c) after mineralization.

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