Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 87: Focussed Session: Solid-liquid Interfaces III
O 87.7: Vortrag
Freitag, 15. März 2013, 12:00–12:15, H31
Calcium oxalate/water interfaces using ab initio Molecular Dynamics — •Leila Salimi Parvaneh1,2, Davide Donadio1, and Marialore Sulpizi2 — 1MPI for Polymer Research, Mainz — 2Physics Department, Johannes Gutenberg University, Mainz
Calcium oxalate is the main component of kidney stones [1]. The presence of peptides such as poly-glutamate has a great impact on the crystalline phase, morphology and growth rate of calcium oxalate [2]. Understanding the biomineralization process and its inhibition requires a detailed microscopic characterization of the water/mineral and water/polymer/mineral interfaces. We performed Density Functional Theory (DFT) based Molecular dynamics simulations [3] to study the structure of the interfaces between Calcium Oxalate Dihydrate (COD) (100) and (101) / water. Our study reveals differences in the coordination of Calcium ions at the surface with water, which could be responsible for a different interaction with biopolymers. We also characterize the interaction between different surfaces of COD and biomolecules. As a first step we consider acetate as a model system containing a carboxylic group and we estimate its binding structure and free energies on different COD surfaces and for different concentration. Preferential binding of carboxylate to the 100 surface is found, therefore explaining recent experimental results on anisotropic growth of COD crystals in the presence of biopolymers [2]. [1] E. L. Prein and C. Frondel, J. Urol. 57, 949, 1947. [2] V. Fischer, K. Landfester and R. Munoz-Espi, Cryst. Growth Des. 11, 1880, 2011. [3] CP2K/QUICKSTEP, http://cp2k.berlios.de/