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The ligand thiol coupling approach introduces reactive disulfide groups into the dextran matrix on the sensor chip. Coupling occurs through thiol-disulfide exchange with native or introduced thiol groups on the ligand.

Chemistry

Ligand thiol coupling relies on thiol-disulfide exchange between a native or introduced thiol group in the ligand and a reactive disulfide on the sensor chip surface. The disulfide group is introduced to the surface via amine coupling of 2-(2-pyridinyldithio)ethaneamine (PDEA).

After immobilization of ligand, excess reactive groups are deactivated with cysteine/NaCl. This approach should be used with care if the analyte requires reducing conditions.

Ligand thiol coupling chemistry

Immobilization procedure overview

The general pattern of steps involved in immobilizing ligand is the same for essentially all covalent immobilization methods:

• Activate the surface by injection of appropriate reagents.
• Inject the ligand solution.
• Inject reagent to deactivate remaining active groups on the surface and remove non-covalently bound ligand.

There may be additional steps depending on the properties of the ligand, the type of sensor surface and the details of the chemistry used.

Lab protocol

Lab procedure Ligand thiol coupling to Biacore sensor chips is available for download on www.cytivalifesciences.com/solutions/protein-research/Interaction-analysis-with-Biacore-surface-plasmon-resonance-SPR/Get-started-with-surface-plasmon-resonance-SPR-interaction-analysis