Surface Plasmon Resonance (SPR) is a popular real-time
label-free method to assess biomolecular interactions
especially in the fields of drug discovery and biosensor
development.
Multi-Parametric Surface Plasmon Resonance (MP-SPR)
scans a broad angular range and records whole SPR curve.
Hence from the same measurement, MP-SPR provides
more information about changes at the surface than
traditional SPR. Additionally, MP-SPR records also bulk
(solvent) effect simultaneously with the binding signal in
every channel. Thanks to the PureKinetics™ feature, bulk
effect can be separated from molecular binding events
in real-time, providing more reliable results and enabling
measurements, which are not possible using traditional
SPR instruments. PureKinetics™ enables measurement
of kinetics in altering dissociation buffers (Application
Note #147) To quantify affinity and kinetic parameters of the biomolecular interaction,
binding at not less than two concentrations of the analyte needs to be measured.
Concentrations need to be in the range close to the dissociation constant (KD),
and usually a few more concentrations are required, as affinity is typically
unknown. Conventionally, the dissociation rate is measured after each analyte
concentration. Additionally, if dissociation is slow, the remaining part of the
bound analyte is removed using a run of regeneration solution between
the sample injections. Ideal regeneration breaks the bonds between
the ligand and the analyte without deactivating the molecules on
the surface. However, such regeneration is sometimes difficult to achieve and also
the ligand is damaged.
The KineticTitration option allows the injection of samples sequentially and the
dissociation is measured only at the end of the whole run. This shortens the time
required for the whole measurement cycle (Figure 1).
KineticTitration is especially useful when:
• results are needed quickly
• there is less time available for assay optimization
(such as for finding a suitable regeneration solution)
• surface is difficult or impossible to regenerate without losing
the activity of the ligan
