Please come hear the talk by Dr. Henry Teng of George Washington University on Friday, November 6th, "Biotic-Inorganic Interface: An Exciting Area for Chemistry." (abstract below)
Biology and inorganic materials, mineral crystals in particular, do not share much common ground in our traditional view of scientific disciplines. Yet biotic-inorganic interface is ubiquitous in the nature as well as in our body systems, thinking about plants’ nutrition uptake from soils and bone healing in the case of skeletal damage. Extensive scientific interests in this field have been fostered in the past decades aiming at understanding how biomolecules and living cells affect the crystallization and dissolution of inorganic crystals. To date, biological research revealed that certain special proteins are involved in the processes, and material studies learned that biogenic crystals are often uniform in size, shape, and orientation. However, from a chemist’s point of view, everything may have started at the biotic-inorganic interface.
In this talk, we will present our study of interactions between amino acids and the crystal faces of calcite using a ‘molecular probing’ approach where we systematically varied the structure and the composition of amino acids. We will show that the chemical reactions at the interface are highly directional and may be controlled by geometry and stereochemistry of the reactants. These results suggest that mineral crystal surfaces may have promoted the origin of life. We will also present our study of microbe-CaCO3 interactions where real bacteria isolated from soils were used to mediate carbonate biomineralization. We found the microbes not only affect the morphology of the resultant crystals, they also control the polymorphic composition. Additional observations suggest that epitaxial growth on the cell surfaces may be critical to this type of crystallization reactions.