Label-Free Biomolecular Interactions

What Applications are Enabled by the ProteOn XPR36 System?

The versatility of the microfluidics in the ProteOn system make it an ideal complement to the drug discovery and development workflow for target screening and characterization studies. The ProteOn system is capable of monitoring up to 36 unique biomolecular interactions simultaneously in a variety of configurations depending on the experimental design:

1 × 1 — full optimization is used to quickly determine optimal assay conditions.

6 × 1 — kinetic screening is used to measure kinetics under different conditions in the same run (One-shot Kinetics).

6 x 6 — single-point screening is used to screen libraries for interactions of interest.

36 × 1 — target screening is used to screen an analyte against 36 targets in a single injection.

The ProteOn XPR36 system can also be used in downstream processing such as protein quantitation for quality control, as SPR can be used to monitor the concentration of small molecules and biologics in crude or impure samples.

Large and Small Molecule Screening
The versatility of the ProteOn XPR36 platform expands the capabilities of SPR analysis, making this technology ideal for use in several stages of the drug development pipeline. With the rise of antibody therapeutics, there is a need for fast and accurate determination of the affinity of candidate antibodies to their targets. SPR can be used for both quantitative large and small molecule screening and qualitative relative ranking of antibody therapeutics (binding or no binding) during drug development. Small molecules can also be screened for activity and desirable adsorption, distribution, metabolism, and excretion (ADME) properties using the ProteOn system. This ability enables the identification of undesirable compounds earlier in the drug discovery process, before considerable time and effort are invested in costly clinical trials.

Validation and Characterization
Unlike endpoint assays such as isothermal calorimetry that measure a binding response after reaching equilibrium, SPR allows for the detection of binding events in real time and the accurate measurement of both association (k_a) and dissociation (k_d) rate constants. This additional information can be helpful in designing potent agonists/antagonists with a fast ka and slow kd or for understanding quantitative structure-activity relationships of small molecules. The unique One-shot Kinetics approach of the ProteOn XPR36 system allows for robust kinetic characterization from a single analyte injection (Yousef 2007). In addition, biomolecular interaction thermodynamics can be characterized by using the ProteOn system to quantify kinetics at different temperatures.

Assay Development and Experimental Optimization
Due to the vast array of applications for SPR, label-free interaction protocols for the ProteOn XPR36 must be tailored to specific experimental needs to obtain high-quality SPR data. The With the deposition of six or more ligands on one sensor chip, the ProteOn XPR36 system’s unique 6 × 6 interaction array allows for flexibility in the design of biomolecular interaction assays, streamlining assay development. Interrogating these different ligands with six separate analytes facilitates experimental optimization by enabling the real-timed detection of up to 36 different biomolecular interaction events simultaneously.

References

Yousef M (2007). Advances in rapid monoclonal antibody screening. American Biotechnology Laboratory 25, 26–28.