| Summary: | The work presented in this dissertation focuses on biomimetic studies of two systems of biosilification: a subset of unicellular algae, known as diatoms, and sea sponges. Chapter I introduces the topics represented in subsequent chapters, including biomineralization, biosilica deposition in sea sponges, biosilica deposition in diatom cell walls, previous biomimetic work, and typical laboratory-based metal oxide formation. Work in Chapter II describes the development of a library of dendrimer-based biomimics of diatom structure-directing organic material. These dendrimers were studied for their ability to precipitate a variety of in vitro silica and titania morphologies, dependent on electrostatic interactions. In Chapter III, two readily available proteases, trypsin and papain, are investigated as potential biomimics of the silicatein enzyme, found in sea sponges as the only known enzymatic example of biosilica formation. The active sites and 3D structure of each protease was studied for its role in metal oxide precipitation. Chapter IV discusses a bottom up approach to metal oxide patterning without the use of harsh chemicals typically used in lithography. The templating and metal oxide formation are characterized using nano-imaging techniques. Chapter V focuses on the biosilicification process in diatoms, presenting work on developing a screening assay of T. pseudonana, whose genome has been fully sequenced. The purpose of the assay is to determine molecules that probe the silicon metabolic cycle that result in morphological changes to the silica frustule. Progress towards the development of this screen is laid out, including growth optimization, plate processing, and plate analysis using colorimetric and fluorescent silica quantitation, as well as flow cytometry. Finally, in Chapter VI, conclusions and future directions of this field are discussed, both in terms of specific work discussed in this dissertation as well as in broader applications.
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