How does MP-SPR work?
The Life Science perspective: From traditional SPR to Multi-Parametric SPR - from measurements to understanding.
See more with MP-SPR!
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 interactions. For instance, PureKinetics™ feature that provides measurements of small molecules, lipids and biomaterials without bulk effect (typical DMSO artefact). MP-SPR widens the application range of traditional SPR from small molecules up to nanoparticles and even living cells. Measurements can be performed even in complex media such as serum.
MP-SPR uniquely provides also information about layer properties. Thickness and refractive index (RI) data can be utilized in material characterization from Ångström thick layers up to micrometers or to ensure conformation of the molecules on the surface.
Animation: How does MP-SPR work?
Above, you can see an animation of a full SPR curve scan. The top graph shows the SPR curve shift due to molecular binding 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.
Lower curve is a sensogram (sometimes called sensorgram). In this case, the angle of peak minimum from full SPR curve above, is plotted against time. 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 meaasured uniquely with MP-SPR.
How does MP-SPR work?
The Material Science perspective: From drug discovery to Ångström precision in coatings and material development.
For the past 20 years, SPR has been used for biomolecular interaction analysis. Now, MP-SPR broadens the application range to material characterization. Surfaces of metals and biomaterials, such as ceramic or polymer coatings, can be characterized with Ångström precision.
The key to the Multi-Parametric Surface Plasmon Resonance is the measurement of full SPR curves. When measured as a function of time (with sampling rate of one curve every few seconds), the results can be calculated to many different physical parameters describing the sample properties or interactions.
- 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.
- 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.
Above, you can see an animation of a full SPR curve scan.
The graph shows a shift in SPR due to formation of a layer at the surface. The new layer can be formed in-situ or ex-situ. 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 layer.
What can you measure with MP-SPR?
The only MP-SPR instrument on the market that can be equipped with multiple wavelengths!
MP-SPR measures uniquely same surface spot at two different wavelengths which enables thickness and refractive index measurement! Feature is useful in all MP-SPR applications but especially with material characterization, biophysics, and cell studies!
MP-SPR Navi™ 200 OTSO, 210A VASA and 220A NAALI instruments can be equipped with up to 3 different wavelengths. Standard configuration of additional wavelength setup is:
- Channel 1: 670nm and 785nm
- Channel 2: 670nm and 785nm
Other wavelengths available by request.
Additional wavelength option should be selected together with the instrument. The configuration is then MP-SPR Navi™ 200-L OTSO, 210A-L VASA and 220A-L NAALI.
Get most out of the feature and combine it with LayerSolver software.
If you already have MP-SPR Navi™ system, contact us to learn how to upgrade it with additional lasers!
Examples of use:
Surface measured with two different wavelengths (here 785 nm and 670 nm). The thickness remains the same in both cases. The difference in the curves is due to the change of refractive index in relation to the measured wavelength.
Measure of thick samples (waveguide effect).
Thickness up to few micrometers (with light nonabsorbing samples) can be measured.
Light absorbing samples, such as porphyrins, cause intensity changes to meaured curves.