Fourier transform infrared microspectroscopy identifies symmetric PO(2)(-) modifications as a marker of the putative stem cell region of human intestinal crypts.

Complex biomolecules absorb in the mid-infrared (lambda = 2-20 microm), giving vibrational spectra associated with structure and function. We used Fourier transform infrared (FTIR) microspectroscopy to "fingerprint" locations along the length of human small and large intestinal crypts. Paraffin-embedded slices of normal human gut were sectioned (10 microm thick) and mounted to facilitate infrared (IR) spectral analyses. IR spectra were collected using globar (15 microm x 15 microm aperture) FTIR microspectroscopy in reflection mode, synchrotron (