AtaGenix Laboratories
AtaGenix Laboratories
AtaGenix provides Surface Plasmon Resonance (SPR) analysis services using Biacore™ systems for label-free, real-time measurement of molecular interactions. SPR delivers quantitative kinetic data (kon, koff) and equilibrium binding affinity (KD) that ELISA alone cannot provide — essential for antibody lead selection, drug-target validation, and regulatory-grade characterization.
Label-Free
No Tags or Labels Needed
Real-Time
kon / koff / KD
Biacore™
Gold-Standard Platform
Multi-Format
Ab, Protein, Small Molecule
SPR works by detecting changes in refractive index when molecules bind to a sensor chip surface. As the analyte flows over an immobilized ligand, association and dissociation are monitored in real time — producing a sensorgram that reveals not just whether binding occurs, but how fast it associates, how fast it dissociates, and how tightly it binds. This kinetic profile is critical for distinguishing between antibody candidates that may show similar ELISA titers but have very different in vivo behavior.
| Application | What SPR Measures | Why It Matters |
| Antibody Affinity Ranking | KD determination for multiple candidates against the same antigen | Select highest-affinity leads from hybridoma, phage display, or single B cell screens |
| Kinetic Profiling | kon (association rate) and koff (dissociation rate) separately | Two antibodies with same KD can have very different kinetics — slow-off is preferred for therapeutics |
| Epitope Binning | Competition between antibody pairs for the same epitope | Group antibodies by epitope class; identify non-competing pairs for sandwich ELISA or bispecific design |
| Drug-Target Validation | Confirm and quantify binding between drug candidate and target protein | Required for IND-enabling data packages; regulatory-accepted method |
| Protein-Protein Interaction | Binding kinetics of any protein pair (receptor-ligand, enzyme-substrate, etc.) | Fundamental research, structural biology, signaling pathway mapping |
| Small Molecule Screening | Fragment binding, hit confirmation, affinity ranking for small molecule leads | Drug discovery fragment-based screening, SAR confirmation |
Biacore™ Gold Standard
We use Biacore™ systems — the most widely cited and regulatory-accepted SPR platform in the industry. Data generated on Biacore is directly compatible with FDA/EMA submission requirements for therapeutic antibody characterization.
Integrated with Discovery Pipeline
SPR analysis is available as a standalone service or as an add-on to any AtaGenix antibody discovery project. Run affinity ranking directly on hybridoma supernatants, phage display hits, or single B cell candidates without purification.
Expert Kinetic Modeling
Our team performs advanced curve fitting and kinetic modeling — 1:1 Langmuir, bivalent analyte, heterogeneous ligand, and mass transport models. You receive not just raw sensorgrams but fully interpreted kinetic parameters with model quality assessment.
AtaGenix's SPR/Biacore™ analysis service provides label-free, real-time binding kinetics (kon, koff, KD) for antibody-antigen, protein-protein, and protein-small molecule interactions. Available as a standalone analytical service or as an add-on to any antibody discovery project (hybridoma, phage display, single B cell). Applications include antibody affinity ranking, kinetic profiling, epitope binning, drug-target validation, and small molecule screening. Deliverables include raw sensorgrams, fitted kinetic parameters, and a detailed analytical report with model quality assessment.
A standardized 4-step process from assay design to interpreted kinetic data.
01
Assay Design
Chip & immobilization strategy
Buffer optimization
Analyte concentration series
02
Surface Preparation
Ligand immobilization
Amine / capture / His-tag coupling
Surface stability validation
03
Kinetic Measurement
Multi-cycle or single-cycle kinetics
Real-time sensorgram acquisition
Regeneration & reproducibility check
04
Analysis & Report
Curve fitting & model selection
kon, koff, KD determination
Sensorgrams + analytical report
Service Scope
| ✓ Antibody affinity ranking (KD) across multiple candidates | ✓ Full kinetic profiling (kon, koff, KD) |
| ✓ Epitope binning / competition mapping | ✓ Drug-target binding confirmation |
| ✓ Protein-protein interaction kinetics | ✓ Small molecule / fragment screening |
| ✓ Multi-cycle and single-cycle kinetics | ✓ Multiple immobilization chemistries available |
| ✓ Deliverables: sensorgrams + fitted parameters + report | ✓ Standalone service or add-on to any Ab discovery project |
| Parameter | SPR / Biacore | ELISA |
| Measurement | Real-time kinetics (kon, koff, KD) | Endpoint binding (yes/no, relative titer) |
| Label Required | No (label-free) | Yes (HRP, biotin, fluorescent) |
| Affinity Data | Absolute KD with kinetic components | Relative (EC50, not true KD) |
| Regulatory Acceptance | FDA/EMA accepted for IND filing | Screening only (not for affinity claims) |
| Best Stage | Lead selection, characterization, IND-enabling | Primary screening, titer measurement |
Add SPR to your antibody project: SPR affinity ranking is available as an optional add-on for Rapid Hybridoma, Rabbit Single B Cell, Phage Display, and Anti-Idiotype projects. For blocking/neutralizing antibody projects, combine SPR competition with our functional screening assays.
What samples can I submit for SPR analysis?
Purified antibodies, recombinant proteins, Fc-fusion proteins, peptides, and small molecules. Crude hybridoma supernatants can be tested using capture-based methods (anti-Fc or Protein A on the chip surface) without prior purification. For best kinetic data, purified analytes at known concentrations are recommended. Minimum sample volume and concentration requirements are provided after assay design consultation.
What is the difference between multi-cycle and single-cycle kinetics?
Multi-cycle kinetics (MCK) uses surface regeneration between each analyte concentration — providing the most robust kinetic data and is the standard for regulatory submissions. Single-cycle kinetics (SCK) injects increasing concentrations sequentially without regeneration — faster and useful when regeneration conditions are harsh or ligand supply is limited. We recommend MCK for final characterization and SCK for rapid screening of many candidates.
Why does KD from SPR differ from EC50 from ELISA?
KD (equilibrium dissociation constant) from SPR measures the intrinsic binding affinity between two molecules in solution-phase kinetics. EC50 from ELISA measures the concentration needed for half-maximal signal in a plate-based assay, which is influenced by coating density, avidity effects (bivalent IgG), and detection system sensitivity. KD and EC50 often correlate but are not equivalent — KD is the true affinity constant and is the accepted metric for regulatory filings.
How many antibody candidates can you test in one run?
For affinity ranking (single-concentration screening), we can test dozens of candidates per run. For full kinetic characterization (multi-concentration, kon/koff/KD), each candidate requires a dedicated concentration series. We typically recommend screening 10–20 candidates by ranking first, then running full kinetics on the top 3–5 leads. Throughput depends on regeneration conditions and assay complexity — our team designs the optimal workflow during consultation.
SPR data quality depends on sample purity, analyte concentration accuracy, and assay design. Biacore™ is a trademark of Cytiva. Kinetic model selection (1:1, bivalent, heterogeneous) is determined by the data and reported in the analytical report. Quote-based pricing.
Contact Us
+86-27-6552-3339
info@atagenix.com
Building C, R & D Building, No. 666, Shendun 4th Road, Donghu New Technology Development Zone, Wuhan
