Ex vivo analysis of the oral epithelium by high-wavenumber Raman spectroscopy

Raman spectroscopy at wavenumber region of 400-1800 cm−1 is an already proved promising technology for objective clinical evaluation of biological tissues to obtain their molecular fingerprint. The study of the high-wavenumber region (2800-3100 cm−1) is also of interest to significantly shorten the diagnosis time due to the intense Raman signal in a narrower range. This work studies parameters dependence, Raman saturation in depth and repeatability of tissue measurements at this region and proposes three indices for quantitative diagnose in oral epithelium. Sixteen oral mucosa biopsies in different thicknesses were evaluated in varying laser powers. The non-saturation of Raman signal up to 120 μm in depth was demonstrated. Three peaks (2874, 2926, 3056 cm−1) attributed to functional groups of interest in oral mucosa were identified from the Raman band deconvolution. The high-wavenumber correspondence with the fingerprint region (400-1800 cm−1) was proven and three diagnose indices ...