Biomedical Aspects of Water Structure in Human and Animal Skin: A Near Infrared-Fourier Transform-Raman Study

NIR-FT-Raman spectra of skin from pig ear, guinea pig and mouse were recorded with excitation at 1064 nm and compared to spectra of human skin. The R((nu) over bar)-representation was used to eliminate the intense Rayleigh band. The total water content in each sample was estimated from the intensities of the OH-stretching vibrations at about 3200 cm(-1). A low-wavenumber band around 180 cm-1 (similar to 5.5 terahertz) was characteristic of a bulk-like liquid water structure. Water content and structure in skin from pig ear, guinea pig and human were similar and different from mouse skin. Differences in loss of bulk water were observed for skin samples after freezing and thawing. Skin biopsies of human skin with various skin tumors showed an increase of water with a bulk-like structure in skin with malignant skin tumors.