Here we present the optimization of fabrication steps for realizing an infrared–visible microfluidic chip to
study single-living cell behaviour in physiological environment by synchrotron radiation FTIR microspectroscopy.
We optimized subtractive and additive lithographic processes on CaF2 substrate, employing XARP
3100/10 photoresist both as etching-mask and for the device fabrication. Using prototype microfabricated
liquid cells 9 and 5 lm thick, we measured the response of small groups of THP1 monocytic cells
to mechanical compression and chemical stimulation with fMLP using conventional IR globar source,
aiming to evaluate biochemical rearrangements of leukocytes during the capillary circulation or recruitment
processes. Stimulated monocytes have spectral features recognizable, differentiating them from unstimulated,
especially affecting the spectral region 1280–1000 cm1, characteristic of nucleic acids and
carbohydrates, and specific band ratios, such as proteins on lipids and methylene on methyl. Spectra variations
have been correlated with biochemical events such as transcription, synthesis of new-proteins and
variations in membrane fluidity.
