Fig. 5
Nano-FTIR spectroscopy of E. coli cells incubated with compound 8 for 20 min at 37 °C and of untreated controls. (a) Topography images of untreated E. coli. The coloured dots indicate the sample spots where the nano-FTIR spectra were recorded. (b) Average nano-FTIR phase spectrum obtained from untreated E. coli compared with the average phase control spectrum from the pure silicon wafer. The E. coli spectrum is averaged from six spectra recorded at the positions of the blue dots in panel a. The vertical scale bar on the vertical axis indicates a 4 degrees change in phase angle. (c) Topography images of E. coli incubated with compound 8. The coloured dots indicate again the sample spots where the nano-FTIR spectra were recorded. (d) Averaged phase spectra obtained from the spots indicated in panel c. Each spectrum is an average of three spectra from corresponding spots on the three lines of dots in the two topography images of panel c. Phase spectra a to f correspond to positions from left to right in the topography plots, spectrum h is the average phase control spectrum obtained from the pure silicon wafer, and spectrum g is the FTIR spectrum of compound 8. The vertical scale bars on the vertical axis indicate a change of 10 degrees in phase angle or of 0.2 in absorbance.
