binding-characterizationlisted

# Binding Characterization: SPR and BLI ## SPR vs BLI Decision Matrix | Factor | Choose SPR | Choose BLI | |--------|------------|------------| | **Sensitivity** | Small molecules, fragments (<500 Da) | Large complexes, antibodies | | **Throughput** | Low-medium (serial) | High (96-well parallel) | | **Sample purity** | Required (clogs fluidics) | Tolerates crude lysates | | **Kinetic resolution** | Higher (better for fast kinetics) | Lower | | **Mass transport** | More sensitive (may distort kon) | Less sensitive | | **Maintenance** | High (fluidics system) | Low (dip-and-read) | | **Sample consumption** | Higher (continuous flow) | Lower | | **Cost per experiment** | Lower chip cost, higher run cost | Higher tip cost, lower run cost | ## Key differences ### SPR (Surface Plasmon Resonance) - **Mechanism**: Detects refractive index changes at gold surface - **Surface**: Gold chip with dextran matrix (CM5, CM7, etc.) - **Flow**: Continuous microfluidics - **Best for**: Small molecules, high-affinity, precise kon/koff ### BLI (Biolayer Interferometry) - **Mechanism**: Measures optical interference pattern shift - **Surface**: Fiber optic biosensor tips (SA, Ni-NTA, AHC) - **Flow**: Dip-and-read (no microfluidics) - **Best for**: High-throughput, crude samples, antibody screening --- ## Troubleshooting: Why BLI works but SPR doesn't | Cause | Mechanism | Solution | |-------|-----------|----------| | **Hydrophobic CDRs** | Adsorb to SPR gold/dextran surface | Add 0.05% Tw