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O: Fachverband Oberflächenphysik
O 66: Plasmonics and nanooptics: Applications and other aspects II
O 66.5: Vortrag
Mittwoch, 14. März 2018, 16:00–16:15, MA 041
Principal component analysis for SEIRA-based monitoring of structural changes in polypeptides — •Rostyslav Semenyshyn1, Mario Hentschel1, Jochen Vogt2, Christian Huck2, Christoph Stanglmair3, Tanja Teutsch4, Cristina Tarin4, Claudia Pacholski5, Harald Giessen1, and Frank Neubrech1,2 — 14th Physics Institute, University of Stuttgart, Germany — 2Kirchhoff Institute for Physics, University of Heidelberg, Germany — 3Max Planck Institute for Intelligent Systems, Stuttgart, Germany — 4Institute for System Dynamics, University of Stuttgart, Germany — 5Institute of Chemistry, University of Potsdam, Germany
Metal nanoantennas with plasmon resonances tuned to the infrared spectral region are perfectly suited for surface enhanced infrared absorption (SEIRA), which has already been applied to chemical analysis and biochemical sensing. Here, we demonstrate the capability of SEIRA for in-vitro observation of folding and unfolding processes of polypeptides monolayers by monitoring the enhanced amid vibrations of the molecules. As a model system, poly-L-lysine (PLL) was bond to the surface of gold nanoantennas utilizing a mixed monolayer of different thiols. We tuned the length of nanoantennas to be resonant at frequency of the amide-I band of PLL and performed SEIRA measurements in D2O based solutions. To analyse the folding process, a principle component analysis (PCA) was applied. PCA is a powerful tool for tracking time evolutions in dynamic systems and is sensitive to slight changes. Applying this approach, we monitored the reversible folding and unfolding of PLL in ultra-low concentrations.