In situ study of ligand-receptor interaction by total internal reflection ellipsometry

Spectroscopic total internal reflection ellipsometry (TIRE) in its dynamic data acquisition mode has been applied for the in situ study of the interactions of monomeric (mGCSF) and dimeric (dGCSF) granulocyte colony stimulating factor and its receptor (GCSF-R) which was immobilized on a thin gold layer. Regression results have shown that the account for signal non-linearity due to analysis of spectroscopic dynamic TIRE data has allowed us to detect small differences in association and dissociation times through the precise determination of the refractive index dispersion. Different binding models were applied in the study of mGCSF and dGCSF interaction with a monolayer of its receptor GCSF-R due to their distinctive changes of refractive index over time.