Binding Assays

Binding Assays

Binding assays are fundamental tools in bioanalysis for studying and quantifying interactions between biomolecules such as proteins, peptides, nucleic acids, and small molecules. These assays provide valuable insights into the affinity, kinetics, and details of these molecular interactions, which are critical in a wide range of applications such as drug discovery, diagnostics, and basic research.

Protheragen-ING Lab offers a full suite of binding assays to support the development and characterization of your biotherapeutic and small molecule drug candidates. Our experts have extensive experience in designing, validating and executing various binding assay formats to meet your specific needs.

Our binding assay capabilities

  1. Receptor Binding Assays: Determine the affinity and kinetics of your drug candidates binding to their target receptors using radioligand, fluorescent, or label-free detection.
  2. Antibody Binding Assays: Characterize the binding properties of your monoclonal and polyclonal antibodies, including epitope binning, competition, and cross-reactivity studies.
  3. Cell-Based Binding Assays: Assess the ability of your compounds to bind to receptors or antigens expressed on the surface of live cells, providing a more physiologically relevant measurement.
  4. Fragment-based Binding Assays: Evaluate the ability of small molecule fragments to bind to target proteins using nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, providing valuable insights into the design of larger, more efficient ligands.
  5. High-Throughput Binding Screens: Leverage our automated liquid handling and detection platforms to rapidly screen large compound libraries and hybridoma supernatants.
  6. Kinetic Binding Assays: Determine the association and dissociation rate constants (kon, koff) of your drug-target interactions using techniques such as surface plasmon resonance (SPR) or biolayer interferometry (BLI).
  7. Equilibrium Binding Assay: Measurement of ligand-target molecule binding at equilibrium using techniques such as radiometric assay, fluorimetry, and SPR to provide information on the affinity of the interaction.

Fig.2 Schematic step diagram describing the PrUF-based ligand-binding assay.Fig. 1 A quantitative fluorescence-based ligand binding assay[1].

Our validated assay platforms

We maintain a wide range of instrumentation and detection technologies to support your binding assay needs, including:

  • Radioligand binding assays using scintillation proximity, filtration, or centrifugation separation
  • Fluorescence-based binding assays using fluorescence polarization, FRET, or TR-FRET readouts
  • Label-free binding analysis by surface plasmon resonance (Biacore) or biolayer interferometry (FortéBio)
  • Cell-based binding measurements using flow cytometry or fluorescence imaging platforms

Binding assay development and validation

Our experienced scientists will work closely with you to develop and validate fit-for-purpose binding assays that meet all applicable regulatory guidelines. This includes:

  • Assay optimization and qualification.
  • Method validation to assess specificity, sensitivity, accuracy, precision, and reproducibility.
  • Cross-validation between different binding assay platforms.
  • Stability assessments for your drug candidate and critical reagents.
  • Statistical analysis and data modeling to derive binding kinetics and affinity parameters.

All binding assay work is conducted in our GLP-compliant bioanalytical lab, with comprehensive documentation and rigorous quality control measures in place.
Contact us today to discuss your binding assay requirements and learn how our experienced team can support the development of your biotherapeutics and small molecule programs.


  1. Breen CJ, et al. (2016). "Development of A Quantitative Fluorescence-based Ligand-binding Assay." Scientific Reports. 6, 25769.