The Use of Surface Plasmon-Based Infrared Spectroscopy to Detect Intercellular Junctions Alterations in Inflamed Intestinal Cells

Intoduction: A novel surface plasmon resonance (SPR) apparatus, based on surface plasmon and waveguide mode spectroscopy, was used to study cellular dynamics with high resolution. In this method, the infrared light produced by the Fouier Transform Infrared (FTIR) generates a surface plasmon wave that propagates on a gold-sample interface and penetrates deep into the sample covering most of the cell height. When monolayer of epithelial cells reaches full confluence a waveguide mode is generated, propagating inside the cell monolayer. Analysis of SPR and waveguide minima provide exact information regarding cell coverage of the surface, cell layer integrity, average cell height and quality of cell-cell contacts.Results: We conducted our experiments utilizing different intestinal cells and demonstrated the systems' ability to monitor real time changes in monolayer formation in different conditions including: (a) high and low cell concentrations, (b) exposure to stress conditions mimicking the development of a specific inflammatory bowel disease and (c) the differences between normal and cancer cell lines. We found that Lipopolysachride (LPS) and Hypoxic conditions caused altered junctional formation, a phenomenon that was dramatically down regulated when we silenced a specific cellular pathway by siRNA methodology. Additionally, we found differences in the monolayer formation-kinetics between normal and cancer cell lines.Conclusions: Our results show the ability of the novel SPR system to detect junctional changes within monolayer of living intestinal cells. Taking into consideration the label free and high resolution features of the SPR, we propose further using of this novel system as an adequate tool to study real time changes of cellular junction dynamics.