Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 90: Sensing, Active Structures and other Applications
O 90.7: Vortrag
Donnerstag, 19. März 2015, 16:30–16:45, MA 144
Poly-peptide sensing with nanoantenna-assisted surface-enhanced infrared spectroscopy — •Rostyslav Semenyshyn1, Frank Neubrech1, Felix Weiher1, Christoph Stanglmair2, Claudia Pacholski2, and Harald Giessen1 — 14th Physics Institute and Stuttgart Research Center SCoPE, University of Stuttgart — 2Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, University of Stuttgart
Surface-enhanced infrared absorption (SEIRA) which uses the enhanced electromagnetic near-fields of resonantly excited metal nanoantennas is a powerful technique to detect minute amounts of molecular substances based on their material-specific vibrations. We used mercaptoundecanoic acid (MUA) functionalized nanoantennas in order to selectively bind poly-l-lysine to gold surface and covered other nanoantennas with specially designed collagen peptides. A tailored flow cell was used to allow for the control of molecular adsorption on the nanostructures and in-situ SEIRA in aqueous solutions. For antennas with different lengths the plasmonic resonance coincides with the amide I and amide II bands of the poly-peptides. Depending on the ratio of the vibrational and plasmonic excitation we observe differently enhanced vibrational amide signals with Fano-type line shapes, confirming the plasmonic nature of the enhancement. In comparison to conventional infrared spectroscopy, such vibrational signals are enhanced by up to four orders of magnitude. This opens up the pathway towards studies of single layers of proteins and their folding behavior.