Description of Research

In graduate school I studied Inorganic Chemistry, and my research focused on making small-molecule models of biological metal centers. Specifically, I synthesized iron-sulfur, iron-nitrogen, and iron-nitrogen-sulfur clusters containing 2, 3, or 4 iron atoms as a way to better understand the active site of the Nitrogenase enzyme.1 Nitrogenase catalyzes the reduction of atmospheric nitrogen using an iron-sulfur metal center, the FeMo cofactor (formula Fe7MoS9X; identity of X is unknown but is probably C, N, or O) to ammonia.2,3

Thermal ellipsoid plot of a synthesized iron-nitrogen cluster, Fe2(μ-NtBu)2Cl42-

During a 2-year, science policy fellowship sponsored by the American Association for the Advancement of Science I worked at the U.S. Environmental Protection Agency on policy issues related to environmental implications and applications of nanotechnology. I subsequently did a post-doc in the Nanoscale Science and Engineering Center at the University of Wisconsin at Madison. Through these experiences, I developed an interest in researching environmentallky-related aspects of nanomaterials.

"Nanotechnology is the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications."⁴ By being able to control and understand materials on the nanoscale (roughly 1-100nm), we can also control the properties of materials in a size-dependent fashion. The size of biological molecules (e.g. proteins and DNA) is in the nanoscale, and as a result, the interaction of nanomaterials with biological systems is an important field of study. Indeed, it has and is leading to breakthroughs medicine and other areas. At the same time, these interactions have the potential for negative health and environmental effects.

Nanoscience is still very much an immature field⁵ and industry is just ramping up its use of the tools and techniques of nanotechnology. Compared to many commodity chemicals, the volumes of nanomaterials produced each year are relatively small, though at the same time, hundreds of products containing nanomaterials have found their way to market.⁶ As a society and as scientists, we are in a unique position: we have the opportunity to benefits and the risks of nanotechnolgy processes and the products before they are widely implemented; we can engage in research and make policy decisions to avoid repeating mistakes of the past, as well as focus efforts on areas with the greatest potential for societal benefits.

At Plymouth State University my research engages undergraduate researchers in the following areas:

1. The development of "greener" synthetic pathways to common nanomaterials.
2. The interaction of nanomaterials with biological molecules and biological systems.
3. The use of nanomaterials for water purification.

Much of the group's current research focuses on nanoscale silver for two reasons: (1) It is relatively easy to synthesize with good control over size and morphology understand standard, benchtop conditions, and (2) it is one of the most widely used nanomaterials in commerce with with a significant potential for exposure to humans and the environment. It's wide use in commerce is due to the fact that silver is antimicrobial, and when produced at the nanoscale, it can be easily incorporated into numerous products.

As a new professor at PSU, my research program is still very much in development. If you are a student at PSU, and you are interested in doing research on environmentally-related aspects of nanotechnology, please contact me! Much of my research involves laboratory chemistry, but I am also interested in continuing to work on environmental, societal, and policy related aspects of nanotechnology.

References

1. Duncan, J.S., Nazif, T.M., Verma, A.K., Lee, S.C. "Iron-Arylimide Clusters [Fe_m(NAr)_nCl₄]^2- (m, n: 2, 2; 3, 4; 4, 4) from a Ferric Amide Precursor: Synthesis, Characterization, and Comparison to Fe-S Chemistry," Inorg. Chem., 42:1211-1224 (2003).
2. Rees D.C., Akif Tezcan F., Haynes C.A., Walton M..Y, Andrade S., Einsle O., Howard, J.B. "Structural basis of biological nitrogen fixation," Philos. Trans. R. Soc. A, 363(1829):971-984 (2005).
3. Einsle, O.; Tezcan, F.A.; Andrade, S.L.A.; Schmid, B.; Yoshida, M.; Howard, J.B.; Rees, D.C. "Nitrogenase MoFe-Protein at 1.16 A Resolution: A Central Ligand in the FeMo-Cofactor" Science, 297:1696 (2002).
4. See www.nano.gov
5. Roco, M. "Nanoscale Science and Engineering: Unifying and Transforming Tools," AIChE J., 50:890-897 (2004).
6. See The Project on Emerging Nanotechnologies' "Nanotechnology Consumer Products Inventory" at http://www.nanotechproject.org/