| Henry Teng, Ph.D. |
Associate Professor,
Department of Chemistry, Columbian College of Arts and Sciences
The George Washington University
2029 G Str. NW
Washington, DC 20052
Email: hteng@gwu.edu
Phone: (202) 994-0112
Fax: (202) 994-0450
Research web site
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| Henry Teng plans his contribution to the proposed Institute
based on his previous and ongoing studies in carbonate biomineralization
and amino acid homochirality. Carbonate minerals, the most important
mineral phase in regulating the chemistry of the ocean and the
atmosphere, occur widely across broad geological settings but
form almost exclusively through biological activities. To establish
a baseline for understanding carbonate biomineralization, he
investigated the fundamental thermodynamics and kinetics of
calcite dissolution/crystallization in the absence and presence
of amino acid using calcite-aspartic acid (Asp) as a model system.
The first result of this research revealed that etch pit morphology
undergoes a transition from the inherited rhombus symmetry (<441>)
in water to a triangle with three steps at [010], [<451>],
and [441 ] in the presence of Asp, indicating that the
interactions of Asp with calcite crystal faces are highly specific
to crystallographic directions during dissolution. This work
was awarded the best paper by the Mineralogical Society of America
in 1998. To determine whether the expression of these unique
crystallographic directions resulted from a kinetic or a thermodynamic
control, he conducted growth experiments in inorganic solution
to determine the surface energetics and step kinetic for calcite
crystallization. This work, published in Science, confirmed
the classic Gibbs-Thomson relationship for the first time in
any crystal system and yielded the direction-specific step edge
free energies along the <441> directions. His interests
in amino acid homochirality stem from the hypothesis that mineral
surfaces may have been involved in the origin of life. More
specifically, mineral surfaces may have directed the earliest
amino acid selection process for the creation of the first self-replication
system. Although proposed by many scientists over at least the
past 50 years, the involvement of crystallographically and structurally
different mineral surfaces in the origin of bioactive molecules
and life has not been explored in any significant way. A preliminary
and collaborative study involving his research on spiral growth
has clearly shown the response of calcite growth features to
the chirality of amino acids. This study, published in Nature,
has sparked significant publicity. Recently, a new and collaborative
initiative to continue the exploration of mineral surface directed
homochirality has been established between his group and the
Carnegie Institute of Washington. A NSF proposal (pending) has
resulted from this collaboration. |
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