Application of fourier-transform infrared ellipsometry to quantify biological molecules in animal tissues

Immunohistochemistry contributes to determine the site of origin of the tumor, helps setting the treatment and the prognosis. However, these assays are both time consuming when treatment may be an emergency, and expensive. Instead of the usual biochemistry we are using for the first time for medical issues Fourier-transform infrared ellipsometry, a non-invasive optical characterization technique used in the semiconductor field to characterize bare substrates and thin films. Working in the mid-infrared (1 to 12 microns), makes this technique sensitive to the molecules present inside the cell (a chemical compound is characterized by a particular mid-infrared radiation absorption pattern). Since the ellipsometric analysis can be performed on tissue slides extended on a specular surface, they may provide the physician with a chemical map of the sample. Here we show that ellipsometry can detect and measure physiological concentration of glycogen diluted in water and retrieve the polysaccharide band in a tissue slide. Our objective is to show that ellipsometry can give a quick and comprehensive analysis of the diverse biological markers forming the living matter.