Biosilicification: the role of the organic matrix in structure control

Abstract

Silicon (although never in the elemental form) is present in all living organisms and is required for the production of structural materials in single-celled organisms through to higher plants and animals. Hydrated amorphous silica is a mineral of infinite functionality and yet it is formed into structures with microscopic and macroscopic form. Research into the mechanisms controlling the process have highlighted proteins and proteoglycans as possible control molecules. Such molecules are suggested to play a critical role in the catalysis of silica polycondensation reactions and in structure direction. This article reviews information on silica form and function, silica condensation chemistry, the role of macromolecules in structure control and in vitro studies of silica formation using biomolecules extracted from biological silicas. An understanding of the mechanisms by which biological organisms regulate mineral formation will assist in our understanding of the essentiality of silicon to life processes and in the generation of new materials with specific form and function for industrial application in the 21st century.

Structure and mechanical properties of selected protective systems in marine organisms

“…Silica (SiO 2 ) is most commonly expressed within the biological materials of sponges and diatoms [76][77][78][79][80][81], and is generally found in its amorphous form [76][77][78][79]. The biomineralization of SiO 2 follows different processes in different organisms.…”

“…spicules, Fig. 8) in a single organism [76,83]. These silica structures are templated by biopolymers into the structural elements of many marine organisms.…”

Novel nanocomposites from spider silk–silica fusion (chimeric) proteins

“…Silica skeletons found in nature are based on nanoscale composites wherein the organic components, usually proteins, are functional parts of the skeletal structures while also serving as silica-forming components (5, 6). As a result, materials' toughness is improved, strength is retained, and fine morphological control is achieved, all hallmark attributes of biological composites.Silica is widespread in biological systems and serves different functions, including support and protection in single-celled organisms, such as diatoms through to higher plants and animals (7,8). The remarkable morphological control in vivo that generates intricate patterns at small-length scales is species-specific and has attracted a great deal of interest in recent years because such features exceed the capabilities of present-day synthetic and technological approaches to materials engineering in vitro.…”

“…Silica is widespread in biological systems and serves different functions, including support and protection in single-celled organisms, such as diatoms through to higher plants and animals (7,8). The remarkable morphological control in vivo that generates intricate patterns at small-length scales is species-specific and has attracted a great deal of interest in recent years because such features exceed the capabilities of present-day synthetic and technological approaches to materials engineering in vitro.…”

Learning from Biosilica: Nanostructured Silicas and Their Coatings on Substrates by Programmable Approaches

“…Among these processes, self-assembled organic matrix has been assumed to play key roles for directing the biosilicification in diatoms, sponges and higher plants (Perry & Keeling-Tucker, 2000;Schröder et al, 2008). Sponges synthesize silica in specifically differentiated cells to form a skeletal element (or spicule).…”