Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Biomaterials and Biopolymers I (joint BP/CPP)
BP 9.9: Vortrag
Montag, 16. März 2015, 16:45–17:00, EB 202
Insights into diatom biomineralization with nanoscale silica-peptide hybrid films — •Helmut Lutz1, Vance Jaeger2, Jim Pfaendtner2, Mischa Bonn1, and Tobias Weidner1 — 1Max-Planck-Institute for Polymer Science, Mainz — 2University of Washington, Chemical Engineering, Seattle
Taking clues from diatom silification we have recently shown that amphiphilic peptides consisting of lysine and leucine (LK peptides) are capable of producing silica wires, spheres and tubes, depending on their secondary structure. Precipitating particles, i.e. mineralization in three dimensions is very different from the two dimensional silification required for the cell walls of diatoms. Hence, we studied mineralization in 2D at the air-water interface. At the interface, slightly different peptides can adopt alpha helical or beta sheet structures depending on the hydrophobic periodicity of amino acids. Upon addition of a silica precursor we were able to obtain peptide-silica hybrid films with a thickness of ~4 nm. By means of surface sensitive techniques, such as sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS) we were able to probe the film composition and interactions between peptides and silica at the early stages of biomineralization. Electron and atomic force microscopy show that the fine structure of the film resembles the in-solution silica precipitates of each peptide. We employed molecular dynamics simulation techniques to complement the experimental insights with a computational model. Our results provide insights into the biomineralization of structured films, which might prove useful in materials design and surface engineering.