Biotemplated syntheses of anisotropic nanoparticles

The technological advances predicted (or, perhaps, demanded) for the twenty-first century are intimately linked to the crystallochemically controlled synthesis of high-performance functional materials. To answer the new hendiatris of 'smaller, faster, better', the manufacture of these materials as nanoparticles has become a scientific noblesse oblige. Direct incorporation into the next generation of electronic devices will necessitate anisotropic forms of these materials, be they nanowires, nanotapes or nanotubes. Chemists have recently discovered that, in addition to the classical methods of anisotropic growth, new routes allow more complex materials to be synthesized in these morphologies. This review describes, using a series of examples, how the morphology of functional materials can be controlled using templated growth mediated by a biopolymer. By involving a biopolymer in the synthetic protocol, anisotropic nanoparticles and assemblages of even quite complex materials can be generated in syntheses that are simple, elegant and highly specific.