Glycosaminoglycan profiling in different cell types using infrared spectroscopy and imaging

We recently identified vibrational spectroscopic markers characteristic of standard glycosaminoglycan (GAG) molecules. The aims of the present work were to further this investigation to more complex biological systems and to characterize, via their spectral profiles, cell types with different capacities for GAG synthesis. After recording spectral information from individual GAG standards (hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparan sulfate) and GAG-GAG mixtures, GAG-defective mutant Chinese hamster ovary (CHO)-745 cells, wild-type CHO cells, and chondrocytes were analyzed as suspensions by high-throughput infrared spectroscopy and as single isolated cells by infrared imaging. Spectral data were processed and interpreted by exploratory unsupervised chemometric methods based on hierarchical cluster analysis and principal component analysis. Our results showed that the spectral information obtained was discriminant enough to clearly delineate between the different cell types both at the cell suspension and single-cell levels. The abilities of the technique are to perform spectral profiling and to identify single cells with different potentials to synthesize GAGs. Infrared microspectroscopy/imaging could therefore be developed for cell screening purposes and further for identifying GAG molecules in normal tissues during physiological conditions (aging, healing process) and numerous pathological states (arthritis, cancer).