Ceramic nanoparticle assemblies with tailored shapes and tailored chemistries via biosculpting and shape-preserving inorganic conversion

• Published in: Journal of nanoscience and nanotechnology Vol. 5; no. 1; p. 63
• Main Authors: Dickerson, M B, Naik, R R, Sarosi, P M, Agarwal, G, Stone, M O, Sandhage, K H
• Format: Journal Article
• Language: English
• Published: United States 01-01-2005
• Subjects: Biomimetics - instrumentation; Biomimetics - methods; Ceramics - chemistry; Chemical Precipitation; Crystallization - methods; Diatoms - metabolism; Nanostructures - chemistry; Nanostructures - ultrastructure; Particle Size; Peptides; Porosity; Proteins - chemistry; Silicon Dioxide - chemistry
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2005.008

A novel biosynthetic paradigm is introduced for fabricating three-dimensional (3-D) ceramic nanoparticle assemblies with tailored shapes and tailored chemistries: biosculpting and shape-preserving inorganic conversion (BaSIC). Biosculpting refers to the use of biomolecules that direct the precipitation of ceramic nanoparticles to form a continuous 3-D structure with a tailored shape. We used a peptide derived from a diatom (a type of unicellular algae) to biosculpt silica nanoparticle based assemblies that, in turn, were converted into a new (nonsilica) composition via a shape-preserving gas/silica displacement reaction. Interwoven, microfilamentary silica structures were prepared by exposing a peptide, derived from the silaffin-1A protein of the diatom Cylindrotheca fusiformis, to a tetramethylorthosilicate solution under a linear shear flow condition. Subsequent exposure of the silica microfilaments to magnesium gas at 900 degrees C resulted in conversion into nanocrystalline magnesium oxide microfilaments with a retention of fine (submicrometer) features. Fluid(gas or liquid)/silica displacement reactions leading to a variety of other oxides have also been identified. This hybrid (biogenic/synthetic) approach opens the door to biosculpted ceramic microcomponents with multifarious tailored shapes and compositions for a wide range of environmental, aerospace, biomedical, chemical, telecommunications, automotive, manufacturing, and defense applications.