Intellectual Merit: Chemical interactions occurring at interfaces between crystalline surfaces and aqueous solutions are crucial to an extraordinarily broad range of scientific and technological topics, including corrosion, heterogeneous catalysts, chemical sensors, and a host of essential everyday products from paints and glues to solvents and cleaners. Geochemists pay special attention to reactions that occur between mineral surfaces and aqueous species - interactions central to weathering and soil formation, hydrothermal ore deposition, pH buffering, biomineralization and biofilm formation, uptake and release of chemicals that affect water quality, and many other natural processes. Building on recent advances in experiment and theory, and harnessing resources of the Carnegie Institution, the Smithsonian Institution, and Johns Hopkins University, this proposed collaborative interdisciplinary research applies a combination of techniques to document chiral (i.e., handed) interactions between minerals and organic molecules. These interactions have profound relevance to understanding such diverse topics as microbial ecology, biomineralization, and the geochemical origins of life. Engineering of chiral mineralmolecule interactions, furthermore, has great potential in many forefront technological applications, including synthesis and purification of chiral pharmaceuticals (a $170 billion annual business), environmental monitoring, planetary life detection, and nanofabrication. Accordingly, this proposal establishes new experimental and theoretical procedures for the characterization and prediction of interactions between organic molecules and crystalline surfaces. On the experimental front, a novel application of DNA microarray technology combined with time-of-flight surface ionization mass spectrometric analysis facilitates the combinatorial investigation of adsorption by many different molecular species on various mineral surfaces. These experiments for the first time will document in detail which molecules adsorb to which surfaces, though without revealing atomic-scale aspects of those interactions. Complementary theoretical modeling integrated with experiments will provide detailed atomic-scale understanding of adsorption geometries on a relaxed crystalline surface. The ultimate objective of this proposal is thus to develop general principles governing the adsorption of organic species on mineral surfaces - principles that will have broad application to science and industry.
Broader Impact: The requested funding will significantly advance understanding of interactions between organic molecules and crystals while developing experimental and theoretical techniques. In particular, exploiting the combinatorial power of microarray technology for the study of mineral surface represents an exciting new direction. This research is especially well suited for participation by undergraduate and graduate students, four of whom have already contributed to these developments during the past 3 years. Public dissemination also remains a high priority. The work has been highlighted on radio programs (including NPR's Earth & Sky), in more than 50 public lectures (including web-available videotaped lectures and the MSA Presidential Address), in general articles (including Scientific American, Elements, and Geotimes), and in the book Genesis published by the National Academy of Sciences (Hazen 2005). Similar outreach activities will be an integral part of the proposed grant. Collectively, these efforts will advance scientific understanding of interactions between molecules and crystalline surfaces, while opening the door to new practical industrial applications for minerals.
This project is being supported jointly by NSF and NASA Astrobiology Institute, which is contributing over 50% of the requested funds.
