[Zurück]

G. Ramer, F. Lu, M. Jin, M. Brandstetter, M. Belkin, B. Lendl:
"External cavity - quantum cascade laser based nanospectroscopy of fungal hyphae";
Poster: 12th Martin and Willis student meeting, Glasgow; 12.09.2013 - 13.09.2013.

Photothermal infrared nanoscopy where the cantilever of an atomic force microscope (AFM)
is excited to oscillations proportional to the local infrared absorbance of a sample has been
shown to allow infrared spectroscopy and imaging at a spatial resolution below 50 nm [1].
This makes it possible to collect infrared images of biological samples at sub-cellular level.
In this work we employ broadly tunable external cavity quantum cascade lasers (EC-QCL) as
light sources to analyze fungal hyphae important for a number of biotechnological process.
The use of such a high repetition rate light source allows resonant excitation of the
cantilever's mechanical resonances. Thereby the sample heating can be can be reduced
significantly in comparison to a ring down approach - a prerequisite for non-destructive
nano-imaging of sensitive biological samples.
We present the first application of photothermal infrared nanoscopy to fungal hyphae and
the first application of quantum cascade laser based photothemal infrared spectroscopy to
biological samples. The collected spectra are shown to be in good agreement with spectra
measured on a Fourier transform infrared (FTIR) microscope.