What is SPRi?

Label-free Biomolecular Interaction Analysis using Surface Plasmon Resonance Imaging

HORIBA Scientific innovative SPRi (Surface Plasmon Resonance imaging) solutions provide a flexible platform which allows designing a complete experiment. The platform consists of biochips, surface chemistry, spotting system, autosampler, SPRi detection system and dedicated software packages.

Label-free molecular interaction analysis

Biochip-based label-free interaction analysis

Surface Plasmon Resonance is an established tool in the life-science sectors. It offers a new generation of label-free biomolecular analysis, providing information on kinetic processes (association and dissociation), binding affinity, analyte concentration and real-time molecule detection.

A large variety of bio-interactions can be monitored, such as antibody/antigen, peptide/antibody, DNA/DNA, antibody/bacteria etc.

High-throughput surface plasmon resonance

Multiplex surface plasmon resonance

Spot up to several hundreds of different molecules on the biochip to take advantage of the multiplexing capabilities for the rapid screening (>100 sensorgrams in parallel) of molecules.

The reactivity of many different species (ligands) submitted to the same environment can be compared with only one sample injection.

Optimization studies for biomolecular interaction analysis (immobilization concentration, pH…) are faster – Saving you time and consumables.

Molecular interactions from crude samples

Molecular interactions from crude samples

A simple fluidic system makes it possible to analyze complex samples such as serum or cell lysates for diagnostic research or drug screening.

Our versatile biosensor can meet the demands of any kind of experimental design.



Information obtained by SPRi

Real-time molecule detection

SPRi Molecule Detection

The detection of a specific molecule in a complex sample (cell extract, serum, milk…) can be performed by immobilizing a binding partner on the biochip.

The SPRi difference image gives a direct Yes/No answer of the binding. When injecting the sample, interacting spots appear as white on the SPRi difference image. The detection of the interaction is label-free, no need to modify your molecules.

Affinity – Kinetics analysis

Kinetics analysis

The affinity (KD) of the interaction describes the strength of binding. However, similar affinities can result in different kinetics. The determination of the kinetic parameters from the sensorgrams (association ka and dissociation kd rates) better characterize the molecular interaction.

Unlike end-point measurements such as ELISA, SPR imaging allows the monitoring in real-time of the molecular interaction, providing information on the kinetics parameters. The high-throughput of SPR imaging allows the parallel analysis of multiple molecules immobilized on the biochip surface.

Typical applications includ

Concentration measurements

The active concentration of a biomolecule in a solution can be easily obtained using a specific binding partner. Because the measurement is based on the affinity interaction between the binding partners, the measured concentration is not influenced by sample heterogeneity (protein folding, aggregation…). In addition, with SPR imaging, the measurement is fast (typical assay time: < 10 min).

Typical applications include:

  • The detection of anti-bovine IgG in human fluids 
  • The detection of anti-rabbit IgG and ovalbumine
  • SPRi is an alternative technique to traditional immunobased assay like ELISA (Enzyme-linked immunosorbent assay).

    Kinetic Information:


    Ka (on rate)

    Kd (off) rate

    KD (Equilibrium 
    Dissociation Constant)









    Experimental Conditions Optimization made EASY with SPRi:

    In addition to attaining the full kinetic profile of your interaction, the high-throughput (more than 100up to 768 samples per day) and multiplexing (monitor few 100 of144 interactions simultaneously) capabilities of HORIBA Scientific SPRi systems allows you to optimize your experimental conditions in short period of time while reducing cost.

    Check out our latest publication on this topic

    The principle of Surface Plasmon Resonance imaging (SPRi)

    Surface Plasmon Resonance (SPR) is an optical detection process that occurs when a polarized light hits a prism covered by a thin (gold) metal layer. Under certain conditions (wavelength, polarization and incidence angle) free electrons at the surface of the biochip absorb incident light photons and convert them into surface plasmon waves. A dip in reflectivity of the light is seen under these SPR conditions.

    Perturbations at the gold surface of the biochip, such as an interaction between probe molecules immobilized on the chip and captured target molecules, induce a modification of resonance conditions which are in turn seen as a change in reflectivity and which can be measured. This is the basis for Surface Plasmon Resonance measurements.

    The SPR imaging technology takes SPR analysis a step further. It is a sensitive label-free method of visualizing the whole of the biochip via a video CCD camera. This design enables the biochips to be prepared in an array format with each active site (spot) providing SPR information simultaneously.

    With the SPRi range of equipment, SPR imaging is provided in a robust and sensitive manner. A broad-beam monochromatic polarized light from a laser diode (at a specific wavelength) illuminates the whole functionalized area of the SPRi-Biochip™ surface (which is mounted within the instrument detection chamber). The high resolution CCD video camera provides real-time difference images across the array format with up to 400 active spots. It captures all of the local changes at the surface of the biochip providing detailed information on molecular binding, biomolecular interactions and kinetic processes.

    Click here to view the SPRi storyboard

    Please click on the images to enlarge them.

    SPRi Storyboard


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Manufactured by HORIBA Scientific

Tags: SPRi, Surface plasmon, molecular interaction

PTI - Horiba

PT. HORIBA Indonesia

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