Biological materials often differ from human materials in both their properties and their constituents. Biomaterials are assembled from the smallest scales out of common materials, and are organized hierarchically with non-uniform properties (anisotropic). In contrast, we manufacture relatively homogenous materials by manipulations at large scales, and with reliance on relatively scarce (often toxic) substances such as metals. Examining biomaterials provides insights into how to design materials that are differentially sensitive to forces along certain directions, which can reduce weight and material usage in structures. They also provide clues to materials that can channel light, sound or heat differentially along certain directions, yielding natural fiber optics, better insulating materials or acoustically absorptive materials. Understanding the principles that result in ground up manufacturing can help to develop these new materials based on common, non-toxic building blocks.
Biologically-derived 3-D Nanoparticle-based Devices
Ken H. Sandhage | School of Materials Science & Engineering | Georgia Tech
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.
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.)
explore synthesis of 3-D functional micrononostructures for advanced devices via chemical conversion of self-assembled biomineralized (bioclastic) templates.
applications low-cost advanced micro-tags (detection, labeling), micro-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
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.
image: Scanning electron microscopy of biosilica from individual cells
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