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DS: Fachverband Dünne Schichten

DS 3: Organic Thin Films

DS 3.15: Talk

Monday, March 16, 2015, 19:15–19:30, H 2032

Nucleation of Vaterite-Phase Calcium Carbonate by Poly Glutamic Acid Peptides on Gold — •Hao Lu, Matthew A. Hood, Rafael Muñoz-Espí, Mischa Bonn, and Tobias Weidner — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Nature uses proteins and peptides containing acidic residues to control the crystal structure of polymorph materials such as calcium carbonate. Among the three most typical anhydrous polymorphs - calcite, aragonite and vaterite - the latter is the most thermodynamically unstable phase, and occurs rarely as biomineral. However, the vaterite structure can be stabilized in vitro by the presence of soluble biomolecules. Previous studies have focused on nucleation in the solution phase. Here we demonstrate interfacial nucleation: vaterite can be stabilized by specifically designed peptides bound to inorganic substrates. As a model system, we used a thiol-terminated poly glutamic acid sequences attached to a gold surface. The data show that the adsorbed peptides act as effective templates for the crystallization of a vaterite film. Using several complementary surface analytical techniques we follow structural changes of the peptide structure induced by the crystallization, which provides molecular-level insights into the biomineralization process of calcium carbonate.