Biologically Templated Nanostructure Assemblies

Abstract

Living organisms are able to manufacture a variety of sophisticated inorganic materials with precise control over chemical composition, crystal structure, and shape. Biomolecules offer unique functionalities such as specific recognition capabilities or catalytic activity. On the basis of these recognition capabilities, biological subunits are able to self‐assemble into defined superstructures with unique shapes. Furthermore, they may respond to multiple physical, chemical, or biological stimuli, and therefore provide a potential means for manufacturing nanomachines. However, naturally occurring inorganic materials are typically based on protein scaffolds with inorganic minerals, for example, iron oxide or calcium carbonate, which limits their technical application. Hence, the knowledge of biological concepts, functions, and design features has been exploited for manufacturing new, technologically important, and functional inorganic nanomaterials that have no isomorphous complement in nature. One major challenge in manufacturing nanostructures by biotemplating has been the need to either modify traditional methodologies derived from chemistry or microelectronics or to develop new synthetic pathways in order to make the material synthesis compatible with the relatively labile biotemplates. Various chemical procedures illustrated by selected examples have been elaborated to direct the nucleation and deposition of inorganic materials (e.g., metals, alloys, or semiconductors) on bioassemblies or to link preformed inorganic building blocks to functional biomolecules. Bioassemblies template complex, multidimensional, and inorganic nanoarchitectures that are typically not available by conventional material synthesis. Recently, the templating ability of natural bioassemblies has been improved by means of genetic engineering. Moreover, it has been demonstrated that the biological functionality of the system may be retained under appropriate conditions, which allows the manufacturing of inorganic nanostructures with motility functions. The use of diverse nanostructured bioassemblies based on both proteins (e.g., cell components such as microtubules, microfilaments, and S‐layers) or microorganisms (i.e., viruses and diatoms) and deoxyribonucleic acid is discussed for their potential of templating of inorganic nanoarchitectures.