How does MP-SPR work?

See more with MP-SPR!
From biomolecular interaction analysis to Ångström precision in coatings and material development. 

Surface Plasmon Resonance (SPR) is an established method for biomolecular interaction analysis. It is popular due to its sensitivity and its real-time label-free principle. Multi-Parametric Surface Plasmon Resonance (MP-SPR) is based on SPR theory, however its advantageous optical setup measures a full SPR curve which enables new insight into the sample’s properties or interactions.

  • PureKinetics™: Small molecules, lipids and biomaterials can be measured without bulk effect (typical DMSO artefact).
  • True thickness: Thickness and refractive index (RI) can be determined by fitting of curves using Fresnel formalism. With additional lasers, a singular solution can be found without known RI or thickness.
  • From Å to µm: Unique wide angle range measurement enables measurement not only of thin layers (Ångströms) but also thicker layers up to a few micrometers. For biomolecular interactions, this expands the application range from small molecules up to nanoparticles and even living cells.
  • No vacuum required: The method allows measurements of samples in air, in a specific gas, humidity or in liquid environment.
  • Real-time interactions: MP-SPR is a real-time method and therefore, allows for instance measurements of swelling of materials when moving from dry to wet environment. It also provides real-time data on material-solvent interactions, for instance.

Animation: How does MP-SPR work?


Above you can see tan animation of a full SPR curve scan measuring molecular binding or measuring physical properties of a layer of interest. The SPR curve (top graph on the right) shifts due to molecular binding or layer formation at the SPR sensor (sometimes called SPR chip). The x-axis is the angle at which the laser excites plasmons. The y-axis shows the level of light intensity reflected from the surface. The dip in the curve (lowest light intensity) shows, when the plasmons are excited. Full SPR curves are used to obtain physical properties of the adsorbed sample.
Plotting the angle of peak minimum from the full SPR curve against time yields a sensogram (bottom graph on the right, sometimes called sensorgram). Here, x-axis represents time, while y-axis shows the shift in angle at which the plasmons are excited. Sensograms are used to obtain kinetic information from the sample.

What can you measure with MP-SPR?

 

The table above shows properties that can be measured with traditional SPR as well as MP-SPR and those that can be measured uniquely with MP-SPR.

For further information on differences between traditional SPR (Biacore with focused beam or localized SPR, imaging SPR) and MP-SPR click here or contact us.

For information on the differences between ellipsometry and MP-SPR click here or ask us about your sample!