3-D Structure of biomolecules at interfaces: Femtosecond vibrational sum frequency generation in the fingerprint region

ANYL 466

Sylvie Roke, roke@mf.mpg.de, Spectroscopy on bio-interfaces, Max-Planck Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany
We present broadband vibrational surface sum frequency generation spectra of bio-degradable polymer films in the fingerprint region. These spectra were obtained using a novel high power infrared laser source, based on a three step chirped pulse amplification scheme. We show that with such pulses we can measure vibrational modes at the surface of bio-degradable polymer films far down into the fingerprint region, which allows us to map modes that specifically correspond to the tertiary structure of the macromolecules. Upon thermal annealing, we observe structural changes that correspond to the breakdown of the existing 3D structure. This clearly demonstrates the possibility of mapping the tertiary structure of macromolecules at interfaces and opens up new routes for the investigation of large molecules at interfaces, like peptides and proteins at interfaces.