What is SPR?

Surface Plasmon Resonance (SPR) is a label-free, real-time, optical biosensor technique for quantifying the affinity and kinetics of biomolecular interactions. The technique involves capturing one binding partner (the “ligand”) to a chip surface and then injecting a solution-phase binding partner (the “analyte”) over the surface. Binding association and dissociation are observed as a change in refractive index plotted on a two-dimensional Sensorgram plot, which correlates to an increase or decrease in bound mass. We use exclusively Biacore 8K/8K+ SPR systems, which are exquisitely sensitive and able to detect even small molecule or fragment binding interactions. SPR can provide valuable information regarding the binding kinetics, affinity, and specificity of biomolecular interactions. 

Benefits of our Biacore SPR Assay service:

Kinetic Analysis: The SPR assay technology allows us to track biomolecular interactions in real-time, enabling the direct measurement of kinetic association and dissociation rates of the binding interaction. There are very few biophysical techniques that are able to supply kinetic data.  

Affinity Determination: Binding affinities can be measured either directly or by calculation from kinetic data. By enabling direct measurement of binding affinities without requiring extensive assumptions or modifications, our SPR assay provides a reliable foundation for assessing molecular interactions, contributing to the rapid screening and iterative improvement of drug discovery campaigns.. 

High Sensitivity and Specificity: Complex biological interactions with affinities spanning the picomolar to millimolar range can be readily detected and quantified with high accuracy due to the sensitivity and specificity of SPR assays. Our Biacore 8K SPR systems effectively have no molecular weight limit, meaning that even weak fragment and small molecule binding events can be observed.  

Label-Free Detection: SPR assays often do not require chemical modifications to the molecules of interest, therefore the native state and functionality of the molecules is preserved, ensuring reliable and physiologically relevant data. 

Quantitative Insights: SPR assays yield precise quantitative data on binding kinetics and affinities, allowing for easy upload and comparison in data management systems such as CDD Vault.  

Learn more about the benefits of our SPR assay service.


Learn more about the benefits of our SPR assay service.

SPR stands out for its high throughput capabilities, unparalleled sensitivity, and ability to provide kinetic data vital for comprehending molecular interactions within biological frameworks. Our team has developed an innovative tagging technique that expands SPR's applicability, making it possible to include proteins previously deemed unsuitable for high-throughput screening because of stability concerns.

Applications of SPR Assays

Target Validation:  Prior to investing resources in developing drugs to target a specific protein or biomolecule, validation of the chosen target is needed to confirm that it is relevant and likely to produce the desired therapeutic effects. SPR assays are key in the validation process by reducing the system to a bimolecular interaction and providing direct and quantified evidence for the interaction.  

Protein-Protein Interactions (PPIs): Investigate protein-protein interactions in a label-free format with our SPR assay, which provides an insight into protein—complex formation, stability, and binding. There are now SPR methods available to probe ternary complex formation, such as with PROTACs and Molecular Glues. 

Drug Discovery: Biophysical assays are utilized for identifying and validating potential drug targets, identifying hits, and prioritizing lead compounds. SPR accelerates the drug discovery process and increases the chance of discovering safe and effective therapeutics. SPR has sometimes been referred to as “The Truth Teller” as it can easily differentiate between on-target versus non-specific binding interactions and can quickly provide indisputable binding evidence that will form a solid foundation for a drug discovery campaign.  

Hit Discovery:  SPR assays are ideal for early-stage drug discovery. High-throughput screening of fragment or targeted small molecule libraries allows for rapid identification of hits.  

Lead Optimization:  SPR assays are crucial to the optimization of lead compounds by providing data such as binding affinity, kinetics, and selectivity. These data provide key insights into the effects of various structural modifications and their influence on kinetics and affinity, thus informing an effective SAR optimization campaign. A common role for SPR in the drug discovery pipeline is as an orthogonal technique to refine and validate hits from ultra-high-throughput techniques such as Affinity Selection Mass Spectrometry (ASMS) to bridge the gap to lead optimization and/or cell-based experiments. 

Mechanism of Action: SPR assays facilitate the exploration of molecular pathways involved in drug-target interactions. They help in identifying the key players and reduce the likelihood of off-target interactions, thereby enabling the optimization of the drug's safety and efficacy. 

Antibody Characterization & Epitope Binning: SPR enables the mapping of molecular interactions at the epitope level, offering detailed structural information about binding sites and specificity. This information is instrumental in guiding the design of small molecules or peptides aimed at disrupting specific interactions. It can also be used to map the reactivity of antibodies against a target protein.  

Enhancing Screening Efficiency with Biacore SPR Assay Services

BLS Plot_Compound ID image
Titration Sensorgram image
Dose-Response Titration image

SPR is the state-of-the-art biophysical technique for characterizing biomolecular interactions, and our SPR assay services utilize the Biacore 8K/8K+ platform to provide high-throughput fragment and small molecule Binding Level Screens (BLS). A typical screening cascade includes a Binding Level Screen, followed by hit titrations to provide validated binders with affinity values. We cover it all: 

  • High-throughput binding level screens 
  • Kinetic assays & titrations—single cycle (SCK), multicycle (MCK), parallel, and 2D assay formats 
  • Affinity assays & titrations—small molecule binding affinity determinations 
  • Variable temperature thermodynamic studies—tease apart the thermodynamic parameters of your interaction 
  • Epitope binning—characterize and sort a library of monoclonal antibodies against a target protein 
  • Concentration & Potency analysis—batch-by-batch analysis of antibodies or other biomolecules

Benefits of our Biacore SPR Service:

Precision Characterization: With the high sensitivity and precision of SPR in the characterization of molecular interactions, you will be able to reliably and reproducibly compare affinity and kinetics between your compounds. Our SPR assays are highly reproducible and the conditions may be transferred in-house or to your other partners. Remember, all data belongs to you.   

Streamlined Development: Expedite the development of small molecules or biologics by identifying potential issues such as specificity early in the process, allowing for swift adjustments that could save invaluable time and resources.  

Robust Data: Our Biacore SPR binding assay service provides robust data that ensures your research is founded on a reliable foundation. Building your drug discovery campaign from the ground up using biophysical techniques such as SPR lends credibility to your program by proving that your drug is on target and specific, saving time, money, and potential heartache in downstream cell or animal studies.  

Custom and Collaborative Biacore SPR Assay Service

Our specialized Biacore SPR assay service is a boutique offering designed to cater to your specific research requirements. Our team of scientists will work closely with you to develop personalized assays either from scratch or from the literature, establish experimental parameters, and analyze data. Additionally, we actively seek collaboration with all our clients. We work with you to ensure that your research is on the right track, and this collaborative approach ensures that all aspects of our Biacore SPR service offering fits your needs from beginning to end. 

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