Once the data are collected for binding of different concentrations of analyte to ligand, captured on the chip surface, they can be analyzed with BiaSimulation to determine the model for binding that gives the best fit to the data, and then to determine the rate constants for association and dissociation (kon and koff), and the binding constant (KD).
The simplest model for binding is 1:1, or, in the case of antibodies and their antigens, 2:1, assuming independent binding of the antigen to each of the sites on the antibody. This model also assumes homogeneity of the ligand and homogeneity of the analyte. BiaSimulation software will readily fit the binding curves if these conditions are met, to provide the desired constants. It will also evaluate the reliability of the fit (Chi2), for statistical purposes.
The software can also be used to facilitate epitope mapping of antibodies to the same antigen. In addition, it allows for analysis of heterogeneous analytes or ligands, binding of analyte to multiple sites on the ligand, determination of the concentration of an analyte in an unknown solution, and corrections for artifacts due to mass transfer.