Lessons from nature : biomimetic approaches to minerals with complex structures

In biology, organic-inorganic hybrid materials are used for several purposes, in particular, for protection and mechanical support. These materials are generally optimized for their function through precise control over the structure, size, shape, and assembly of the component parts and can be superior to many synthetic materials. The shapes and forms of minerals encountered in nature strongly contrast with those that are generally formed in a synthetic environment. According to current understanding, this is achieved through different modes of control: their shape can be controlled by restricting their growth to a confined space or by influencing their preferred direction of growth; in addition, for crystalline materials, polymorph selection and oriented nucleation are achieved through specific interactions between a template or additive and the developing nucleus. Also, controlled arrangement of nanoparticles into superstructures can lead to a complex structure. The understanding and, ultimately, the mimicking of these processes will provide new synthetic routes to specialized organicinorganic hybrid materials. On the other hand, transformation of existing complex hierarchical natural structures such as wood or diatom frustules into other materials using shape-preserving chemistry is another approach toward minerals with complex biomimetic structure. The theme topic in this issue will focus on recent biomimetic and bioinspired approaches used to achieve control over the shape and organization of mineral and organic-inorganic hybrid materials. The different contributions will also highlight the advantages of these methods for advanced materials synthesis, and possible applications will be discussed