Biocatalytic Synthesis of a Nanostructured and Crystalline Bimetallic Perovskite-like Barium Oxofluorotitanate at Low Temperature

Abstract

Silicatein, an enzymatic biocatalyst from the marine sponge Tethya aurantia, is demonstrated to catalyze and template the hydrolysis/condensation of the molecular precursor BaTiF6 at low temperature to form nanocrystalline BaTiOF4, an orthorhombic oxofluorotitanate. The kinetics of hydrolysis and growth were studied in-situ via pH profiling and quartz crystal microbalance (QCM) techniques. The composition and structure of the resulting BaTiOF4 microstructures on the silicatein surface were characterized using FT-IR spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction. The silicatein-mediated hydrolysis/condensation of BaTiF6 generates nanocrystalline BaTiOF4 (a high-temperature intermediate to BaTiO3) at 16 degrees C without any added acid or base, and the growth is templated along the protein filaments into floret microstructures. The unique combination of silicatein and the single-source molecular precursor has allowed a multimetallic perovskite-like material to be biocatalytically synthesized, in vitro, for the first time.

Interactions of biomolecules with inorganic materials: principles, applications and future prospects

“…Using such an approach a wide variety of 'small' and 'simple' biomolecules such as amino acids through to macromolecules such as proteins and DNA and more complex assembled structures thereof have been explored for fabricating novel materials. 1,[14][15][16][17][18][19][20][21][22][23][24][25][26][27] In order to develop this approach further, it is essential to understand in detail how biomolecules interact with inorganic materials, and to be able to identify the 'rules' or 'guiding principles' that govern interaction which could then be used to explain and then predict behaviour. An understanding of biomoleculeinorganic materials interactions would be highly fruitful not only to understand biological mineralization processes but also to design novel materials and processing technologies for applications in fields as diverse as biological imaging and biosensors, implant integration, [28][29][30][31][32] food and drug handling, and electronic materials (Fig.…”

Enzyme-mediated synthesis of ceramic materials

“…In addition, silicatein was found to be active in the synthesis of TiO 2 , 50)52) ZrO 2 , 51) Ga 2 O 3 , 53) or BaTiOF 4 , 54) which is of significance because site-selective precipitation of SiO 2 or TiO 2 has been difficult by conventional techniques. An example of silicateinmediated TiO 2 is shown in Fig.…”

Bioinspired Synthesis of Organic/Inorganic Nanocomposite Materials Mediated by Biomolecules

“…Silicatein filaments also demonstrated the ability to form titanium dioxide, gallium oxohydroxide (GaOOH) and gamma-gallium oxide (gamma-Ga 2 O 3 ) in vitro, which are three inorganic semiconductors that biological species have never naturally produced (Kröger et al 2006;Sumerel et al 2003;Curnow et al 2005;Kisailus et al 2006). An enzymatic biocatalyst from the marine sponge Tethya aurantia, was used to catalyze and template the hydrolysis and condensation of the molecular precursor BaTiF 6 at low temperature to form nanocrystalline BaTiOF 4 (Brutchey et al 2006). Amorphous silica (or silica glass) is widely used in different applications, such as membranes, columns, heat-proof materials, optical communication fibers, and catalysts in organic synthesis (Jensen et al 2009).…”