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Diatom Nanobiotechnology:


Design Principles for Enhancing the Catalytic Activities of Enzymes and Metal Nanoparticles immobilized on Diatom Biosilicia


Professor Dr. Nils Kröger,Technische Universität Dresden; Molecular Bioengineering, B CUBE Arnoldstrasse 18 01307 Dresden

Professor Dr. Eike Brunner, Technische Universität Dresden; Fachrichtung Chemie und Lebensmittelchemie, Lehrstuhl für Bioanalytische Chemie Bergstraße 66 01069 Dresden


 Figure 1: Structures of Diatom Silica A) False color electron microscopy images of individual cells from five diatoms species: Eunotia sp. (left), Triceratium sp., (middle, top), Amphitetras sp. (middle, bottom), Asterolampra sp. (right, top), Arachnoidiscus sp. (right, bottom). B) Detail of Coscinodiscus asteromphalus. C) Detail of Stephanopyxis turris.

Diatoms are single-celled microorganisms capable of forming remarkable SiO2 (silica) based cell walls. Diatom biosilica exhibits hierarchical patterns of nano- to microscale features, which endow the material with interesting properties that are difficult to reproduce synthetically. The project combines methods for the deposition of inorganic materials under mild reaction conditions with genetic manipulation of diatom silica biogenesis to synthesize hierarchically structured organic-inorganic hybrid materials with interesting catalytic and optical properties. Diatom biosilica uniformly coated with enzymes and Pt nanoparticles will be studied with respect to the favorable catalytic properties of diatom biosilica. The catalytic tests will be accompanied by extended analytical studies - especially of the silica surface properties - in order to interpret the catalytic behavior with respect to the hypothesized influence of the species-specific silica structures. Moreover, it is planned to generate transgenic diatom strains that expose tailored functional proteins in selected regions of the silica scaffold. This will be exploited for the deposition of functionalized inorganic nanoparticles in well defined regions of the silica scaffold. The incorporation of receptor/ligand proteins is aimed at enabling the site-specific attachment of appropriately modified semiconductor nanoparticles. 2D arrays of diatom cell walls will be generated alternatively by micromanipulation or by the floating assembly method. Through self-assembly of receptor/ligand modified diatom silica on top of pre-fabricated 2D arrays, we are aiming to generate 3D superstructures of this unique biological material. The optical properties of these arrays will be studied in detail.