Method for Time-Resolved Monitoring of a Solid State Biological Film Using Photothermal Infrared Nanoscopy on the Example of Poly-L-lysine

作者：Ramer Georg; Balbekova Anna; Schwaighofer Andreas; Lendl Bernhard^*

来源：Analytical Chemistry, 2015, 87(8): 4415-4420.

DOI：10.1021/acs.analchem.5b00241

We report time-resolved photothermal infrared nanoscopy measurements across a spectral range of more than 100 cm(-1) (1565 cm(-1) to 1729 cm(-1)) at nanoscale spatial resolution. This is achieved through a custom-built system using broadly tunable external cavity quantum cascade lasers in combination with a commercially available atomic force microscope. The new system is applied to the analysis of conformational changes of a polypeptide (poly-L-lysine) film upon temperature-induced changes of the humidity in the film. Changes of the secondary structure from beta-sheet to alpha-helix could be monitored at a time resolution of 15 s per spectrum. The time-resolved spectra are well comparable to reference measurements acquired with conventional Fourier transform infrared microscopy.

• 出版日期2015-4-21