Sensor chip CAP
The Biotin Capture kit is special designed to capture biotinylated analytes on a streptavidin surface (1). The sensor chip is pre-coated with an oligo sequence. Step 1 is the injection of the CAP-reagent, the complementary oligo-sequence to which streptavidin is immobilized. Step 2 is the injection of the biotinylated ligand. By varying the injection time, the amount of captured ligand can be regulated. Step 3 is the actual interaction. Because of the nature of the oligo interaction, the surface can be regenerated with mild solutions. For the total regeneration of the sensor chip, a regeneration solution of 6 M Guanidine-HCl in 0.25 M NaOH is used. This will break the oligo interaction leaving the surface clean for the next capture of CAP-reagent.
If over time an extra cleaning is required, use a two-minute injection with 30% acetonitrile in 0.25 NaOH.