Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )

O 36.18: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B2

In Situ Measurements of Protein Solutions with Nanoantenna Enhanced Infrared Spectroscopy — •Robert Wolke¹, Jörg Bochterle¹, Frank Neubrech^1,2, and Annemarie Pucci¹ — ¹Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany — ²4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

Fourier Transform Infrared spectroscopy (FT-IR) of aqueous solutions is a difficult task due to the strong absorption bands of water in the range of 1550-1750 cm⁻¹ and 3000-3700 cm⁻¹. In order to enable measurements in transmission geometry, the thickness of the water layer should not exceed 10 µm. We created a microfluidic device (MFD) having nanoscopic metal rods inside the flow channel to utilize the signal enhancement seen in Surface-Enhanced Infrared Spectroscopy (SEIRS). This approach allows in situ SEIRS experiments in transmission geometry. Using photolithography, a flat microfluidic channel is inscribed on a calcium fluoride (CaF₂) wafer and closed off using a second CaF₂ wafer. SEIRS enhancement is achieved by micrometer long gold nanoantennas featuring localized surface plasmon resonance (LSPR) frequencies in the IR range. They are attached to the surface of the second wafer and can be exchanged easily. Our setup enables many new possibilities like in situ monitoring of protein binding kinetics to functional layers on the antennas or temperature dependent monitoring of protein conformation changes.