# Binding Characterization

Guidance for SPR and BLI binding characterization experiments.

- Repository: https://github.com/FreedomIntelligence/OpenClaw-Medical-Skills (3090 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-07-21
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add FreedomIntelligence/OpenClaw-Medical-Skills --skill binding-characterization -g -a claude-code -y`
Codex: `npx skills add FreedomIntelligence/OpenClaw-Medical-Skills --skill binding-characterization -g -a codex -y`
Cursor: `npx skills add FreedomIntelligence/OpenClaw-Medical-Skills --skill binding-characterization -g -a cursor -y`
Gemini CLI: `npx skills add FreedomIntelligence/OpenClaw-Medical-Skills --skill binding-characterization -g -a gemini-cli -y`

## Description

Guidance for SPR and BLI binding characterization experiments. Use when: (1) Planning binding kinetics experiments, (2) Troubleshooting poor/no binding signal, (3) Interpreting kinetic data artifacts, (4) Choosing between SPR vs BLI platforms.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# 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% Tween-20, use CM7 chip with longer dextran |
| **Aggregation** | Mass transport artifacts in SPR fluidics | Filter sample (0.22μm), reduce ligand density |
| **High instability** | Degrades during continuous flow | Shorter cycle time, add stabilizers (trehalose 5%) |
| **Charge mismatch** | Nonspecific binding to charged dextran | Adjust buffer pH ±1 from pI, add BSA 1mg/mL |
| **Slow dissociation** | Long regeneration needed (damages ligand) | Use BLI (disposable tips) |

The rest: https://github.com/FreedomIntelligence/OpenClaw-Medical-Skills/blob/HEAD/skills/binding-characterization/SKILL.md