How does MP-SPR differ from traditional SPR?

Don't stay in the dark, see more with MP-SPR!


While the physical principles of MP-SPR are based upon well-established SPR principles, the measurements and experimental possibilities of this technology go far beyond the capabilities of traditional SPR.

What can MP-SPR measure that traditional SPR cannot?

Traditional SPR can provide information on kinetics of molecular interactions. MP-SPR provides all that traditional SPR can and moreover also optical and physical properties of the layer(s).

Molecular interactions

Layer properties

Kinetics (kon, koff) Refractive index (n)
Affinity (KD) True thickness (d)
Concentration (c) Extinction coefficient (k)
Adsorption/Absorption Density (ρ)
Desorption Surface coverage (Γ)
Adhesion Swelling (Δd)
Electrochemistry (E, I, omega) Optical dispersion (n(λ))

SPR and MP-SPR measures, only MP-SPR measures

PureKinetics™

Reference channel VS In-line bulk effect measurements

MP-SPR uniquely allows measurements of bulk effect in-line, providing high quality kinetic measurements. The technique does not require a reference channel, it tolerates even 5% changes in DMSO concentration during a run and it does not require multiple DMSO injections for calibration.

Freedom of sensor surface

Gold and thin polymers VS gold, PET, PS, cellulose, graphene, SiO2, cellulose, living cells, ...

While traditional SPR works mostly with gold and thin polymer layers, MP-SPR enables virtually any material to be used as sensing surfaces for SPR studies. The SPR sensors can include biosensor hydrogels, metals, semiconductors and dielectrics, such as CMD- and other functional hydrogels, Al2O3, SiO2, nylon, cellulose, PS, PP, PET, living cells…  Without the MP-SPR ability to scan through a wide range of angles, other materials are “invisible” to traditional SPR. 

Beyond nanometers

Up to 150 nm VS from 5Å up to 5 µm

Traditional SPR works with thickness up to 150 nm, MP-SPR can work with layers up to several microns thick, allowing work with living cells amongst others. 

Conformational changes in real-time

A thickness VS true thickness

Thanks to multiple wavelenghts and scanning angular measurement, MP-SPR offers Ångström resolution, which makes it possible to observe dynamic changes in the structure of the layers, such as conformational change. 

Easy surface modification of SPR chips

Ready made chips VS ready made chips and your own chips

MP-SPR sensors (or "SPR chips", "SPR crystals") can be easily modified ex-situ by a number of methods including dip coating, spray coating, Langmuir-Blodgett, atomic layer deposition (ALD), chemical vapour deposition (CVD) and many other methods. Thanks to our elastomeric coating on prism, there is no refractive index oil needed, which makes the sensor handling and replacement very easy. It also allows easy characterization of the surface with AFM or other microscopy techniques after interaction measurements.

Absolute measurements

Relative VS absolute measurements

Traditional SPR is a relative measurement and cannot provide measurements in SI units without a number of assumptions. MP-SPR is an absolute measurements that can easily be verified with numerical methods.

MP-SPR

Multi-Parametric Surface Plasmon Resonance

  • Absolute measurement due to optics goniometric arrangement
  • Measurement in a wide angular range enabling whole SPR curve monitoring 
  • Follow peak minimum position, total internal reflection as well as peak minimum intensity parameters and get more information about interaction.
  • PureKinetics™ enabling inline measurement of bulk effect
  • Measurement of real time molecule molecule interactions (affinity and kinetic) as well as thickness and refractive index to ensure conformation.
    Measurements from first selection of molecules up to uptake mechanisms: Quantify drug-material, drug-target, drug-lipid membranes and even drug-living cell monolayer interactions.
  • Measurements from ultra-thin (angstroms) to thick layers (up to few micrometers)
  • Measurements in gas and in liquid (even organic solvents)
  • Measurement on: Au, Cr, Al, Ag...,
  • Wide range of sensor surfaces available inorganic layers: SiO2, Al2O3, TiO2 ... or functionalized surfaces like carboxymethyldextran (CMD) for biomolecule binding
  • Possibility to combine electrochemistry and SPR measurements

Traditional SPR

such as Biacore, focused beam SPR, imaging SPR, ...

  • Only relative measurement due to optics
  • Measures only small angular area
  • Peak minimum position is monitored
  • Requiring multiple background solution injections for bulk signal calibration
  • Measurement of molecule molecule inteactions (affinity and kinetic)
  • Measurement on thin layers
  • Measurement in aqueous liquids
  • Measurement on gold substrate
  • Narrow range of measurable sensor surface
  • Possibility to combine SPR with electrochemistry only in certain cases

Goniometric SPR

comparison_with_SPR_MP-SPR_netti.png

  • MP-SPR uses goniometric arrangement
  • Typical range is 1.0-1.4 of bulk RI
  • Wide angular range (up to 38 degrees)

See an animation, how full SPR curve is acquired on our Technology page.

Focused beam SPR optics

SPR_traditional.png

  • Traditional SPR, such as Biacore, use focused beam arrangement
  • Typical range 1.33-1.38 of bulk RI
  • 10 deg of angular range

Parameters measured with both traditional SPR and MP-SPR:

1   Angular position of SPR peak min is the only parameter measured by traditional SPR. It is typically presented in a traditional SPR sensogram.

Parameters measured only with MP-SPR:

2   Intensity of SPR peak min. depends on the sensor material and the media. Unlike others, SPR Navi™ is able to measure in liquid as well as in gas, on metals, metal oxides and hydrogels.

3  Total Internal Reflection (TIR) value is dependent on the bulk properties around the sensor and it is utilized for dn/dc calculation.

4   Steepest falling and raising slope shows the most sensitive measurement area for the fast fixed angle measurements. 

5  SPR-width at 3 different levels defines the shape of the SPR peak. It contains information on light absorption by the binding molecules and therefore, enables characterization of absorbing coatings and samples. 

6   Another wavelength pair can be used for all measurements. This resolves layer thickness and RI.