Protein Interaction Testings
Biotherapeutic Drug Discovery With SPR

Biotherapeutic Drug Discovery With SPR

At Seattle Genova, we are providing the most comprehensive lead characterization of high affinity biologic interactions with SPR. We also  offers comprehensive Fc receptor & C1q binding tests with SPR technology. Seattle Genova offers a well-established SPR assay for ranking drugs according to their ability to interact with the most abundant plasma proteins, limiting their availability and pharmacological potency.

Surface plasmon resonance (SPR) analysis gives significant binding characteristic information for an antibody to its binding partner, such as binding specificity and affinity (KD). In current years, SPR has been increasingly utilized in biosimilar improvement as a basis of the comparative analytical similarity assessment. Although there is no systematic study illustrating how to qualify SPR assays, there are several SPR result types (outputs) that have been utilized for assay qualification in publicly accessible regulatory documents. The mixed usage of SPR output can confuse and can be misleading when comparing binding attributes among antibody molecules.


SPR is often utilized for target identification and ligand fishing in proteomics, target assay validation for High Throughput Screening (HTS), rapid affinity ranking and detailed kinetics of interaction for small molecules binding to target proteins lead optimisation, early ADME, stratification of patient response to therapeutics in clinical trials, immunogenicity assessment containing anti-drug antibody (ADA) responses of biotherapeutics, vaccine development containing immune response analysis, and even in manufacturing such as procedure and batch QC of therapeutic antibodies and proteins.

SPR use has a significant impact on the development and discovery of new drugs. It is well recognised that finding and developing small molecule drugs is an expensive, time-consuming, and unsuccessful endeavour. The adoption of technologies like SPR to quickly and precisely evaluate the activity and binding properties of target molecules throughout the whole discovery and development process is necessary due to the large investment requirements and very poor success rates.

SPR biosensors can utilise nanoparticles as carriers for therapeutic implantation when combined with nanotechnology. For instance, nanoparticles can be utilised to deliver therapeutic compounds in a targeted manner in the treatment of Alzheimer's disease. SPR biosensing is generally outperforming other methods in the biomedical industry because it is label-free, less expensive, usable in point-of-care settings, and able to deliver quicker findings for smaller study cohorts.

1. Biotherapeutics Affinity Testings

Lead characterization of high affinity biologic interactions with SPR

Protein therapeutics, or biologics, are known for having good specificity for their therapeutic targets and this often affords fewer side effects than small molecule drugs. Biologics are an achievable route for targeting protein–protein interactions, cell surface receptors, and other difficult-to-drug therapeutic targets.

Target binding characterization is an important analytical step for the selection of high affinity (KD<1nM) and highly specific biologics regardless of the types of molecules. 

Kinetic analysis further describes the components of association and dissociation that comprise the overall affinity interaction

2. Fc Receptor Binding Asaay

Fc Receptors

The human and non-human primate FcγR family consists of several activating receptors (FcγRI, FcγRIIa, FcγRIIIa) and a single inhibitory receptor, FcγRIIb.


C1q serves as a recognition and regulatory protein for the complement cascade. It is a protein complex involved in the complement system, which is part of the innate immune system.


Fc receptor-like proteins, consisting of six members (FCRL1-6) were originally identified as homologs of FcγR but were for a long time regarded as orphan receptors, mostly expressed on B-cells.


Tripartite motif-containing protein 21 (TRIM21) is a cytosolic protein expressed in almost all cell types but highly expressed in immune cells


DC-SIGN binds to the CH2–CH3 interface of the Fc domain of IgG, owing to the opening up of the site, where DC-SIGN binds due to the charged sialic acid.

3. Serum Protein Binding (ADME)

The binding of therapeutic compounds to plasma or serum proteins is an important factor to consider when assessing the Absorption, Distribution, Metabolism, Excretion (ADME) and Pharmacokinetics (PK) profile of a drug.

The use of Biacore systems for drug-target and drug-ADME target studies during both hit-to-lead and lead optimization phases of drug development can provide important insights on how plasma protein binding may impact drug dose and/or drug efficacy.

Service Highlights 

  • As new hits are generated and optimized into lead candidates, we can accurately characterize target binding for panels of advanced hits all the way to high affinity leads.

  • Our service is 3- to 6-fold faster than traditional characterization services

  • We use less sample (50% less analyte)

  • No analyte dilutions required

  • Baseline stability coupled with the time and injection reducing advantages make our service an optimal assay platform for high affinity biologic characterization. 

  • For each receptor binding assay, the receptors are either immobilized directly on the chip or they are captured with an anti-his antibody is immobilized onto a CM5 chip. 

  • Multiple concentrations of testing protein flow through the Fc receptor.

  • SPR sensorgrams are fit to obtain the affinity (KD) between the testing protein and Fc receptor. 

  • With state-of-the-art equipment and scientific expertise in drug-serum protein binding test, Seattle Genova is focused on providing cost-effective, high-quality, reproducible data and flexible solutions with fast turnaround times. 


  1. Dove, A. (1999) Drug screening - beyond the bottleneck. Nat. Biotechnol. 17, 859–863.

  2. Rademann, J. and Jung, G. (2000) Techview: drug discovery: integrating combinatorial synthesis and bioassays. Science 287, 1947–1948.

  3. Donghui, Y., Blankert, B., Vire, J. C. and Kauffmann, J. M. (2005) Biosensors in drug discovery and drug analysis. Anal. Lett. 38, 1687–1701.

  4. Fang, S., Lee, H. J., Wark, A. W. and Corn, R. (2006) Attomole Microarray detection of microRNAs by nanoparticle-amplified SPR Imaging measurements of surface polyadenylation reactions. J. Am. Chem. Soc. 128, 14044–14046.

  5. Dove, A. (1999) Drug screening - beyond the bottleneck. Nat. Biotechnol.17, 859–863.

  6. Rademann, J. and Jung, G. (2000) Techview: drug discovery: integrating combinatorial synthesis and bioassays. Science287, 1947–1948.

  7. Zeng S, Baillargeat D, Ho HP, Yong KT (May 2014). "Nanomaterials enhanced surface plasmon resonance for biological and chemical sensing applications". Chemical Society Reviews. 43 (10): 3426–3452. 

Lead Characterization Of High Affinity Biologic Interactions With SPR
Lead characterization of high affinity biologic interactions with SPR
Fc Receptor Binding Asaay
Seattle Genova offers comprehensive Fc receptor & C1q binding tests with SPR technology.
Serum Protein Binding (ADME)
The binding of therapeutic compounds to plasma or serum proteins is an important factor to consider when assessing the Absorption…

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