Biomimetic Materials and Processes

Project 1

Biologically-derived 3-D Nanoparticle-based Devices
Ken H. Sandhage | School of Materials Science & Engineering| Georgia Tech

approach
Bioclastic and Shape-preserving Inorganic Conversion (BaSIC). Such shape-preserving synthethic chemical conversion of 3-D biologically-derived structures can yield large numbers of self-assembled functional devices.

accomplishments
developed new processes for the shape-preserving chemical conversion of bioclastic templates into functional |non-natural| device chemistries (e.g., MgO, CgO, TiO2, ZrO2, BaTiO3, polymers, etc.)

research objective
explore synthesis of 3-D functional micro“nonostructures for advanced devices via chemical conversion of self-assembled biomineralized (bioclastic) templates.

applications low-cost advanced micro-tags |detection, labeling|, micro#045;sensors ( rapid, minimally-invasive sensing), micro-fibers (lightweight composites), micro-mixers ( lab-on-a-disc), micro-reactors (environmentally remediation(, and micro-capsules (drug delivery).

image: MgO-converted microshell

Project 2

Biosilification
Nils Kroger | School of Applied Physiology | Georgia Tech

Kroger and collaborator Nicole Poulsen have developed a technique to genetically engineer diatoms. The process allows insertion of mutated or foreign genes into the genome of the diatom Thalassiosira pseudonana. Kroger believes this technique will enable the creation of diatoms with novel silica structures.

Genetic manipulation of diatoms will increase the understanding of their cellular biochemistry and potentially enable the use of these organisms for the production of commercially valuable compounds and materials, Kroger said. But inserting a gene through the strong silica cell wall is difficult. The wall must be penetrated, but not broken, and the foreign gene must be accepted into the diatom's genome, he explained.

To insert the genes, such as those that encode different silaffins, through the diatom cell wall, Kroger and Poulsen use a technique called microparticle bombardment. DNA-coated tungsten particles are "shot" on the diatoms under high heliumpressure, thus enabling them to penetrate the strong diatom cell wall. The diatom incorporates the introduced DNA into its genome, and selection of the transfected cells is achieved using the antibiotic nourseothricin. When new genes are introduced with the technique developed by Kroger and Poulsen, they can be expressed constantly or be turned on and off when necessary.

Research in Silica Biotechnology aims to establish the molecular tools allowing the creation of mutated Diatoms that produce tailored silica nanostructures adapted for nanotechnological applications.

Project 3

Biocatalysts
Jim Spain | School of Civil and Environmental Engineering | Georgia Tech

Bacterial degradation of aromatic compounds under aerobic conditions is often initiated by multicomponent dioxygenase enzyme systems. Since many aromatic compounds are known to be toxic and/or carcinogenic, these bacterial enzymes are important for removing compounds such as benzene, toluene, naphthalene, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and nitroaromatics from the environment. Recently, there has been a great deal of interest in these broad-substrate enzymes for the production of chiral synthons used in the preparation of a wide range of biologically active chemicals and pharmaceuticals, including inositol phosphates, prostaglandins, and antitumor agents. The use of these enzymatic routes for the formation of useful products from what were previously considered toxic waste materials is a driving force for the field of †green† chemistry

image: The combined action of immobilized hydroxylaminobenzene mutase and zinc in a flow-through system catalyzes the conversion of nitroaromatic compounds
to the corresponding ortho-aminophenols, including a novel analog of chloramphenicol.