Raman spectroscopy: a structural probe of glycosaminoglycans

We report the first Raman spectroscopic study of the glycosaminoglycans chondroitin 4-sulfate, chondroitin 6-sulfate and hyaluronic acid, both in solution and in the solid state. To aid in spectral identification, infrared spectra were also recorded from films of these samples. Vibrational frequencies for important functional groups like the sulfate groups, glycosidic linkages, C-OH and the N-acetyl group can be identified from the Raman spectra. Certain differences in the spectra of the different glycosaminoglycans can be interpreted in terms of the geometry of the various substituents, while other differences can be related to differences in chemical composition.