The five-channel BI-4500 SPR analysis system with integrated auto-sampler was used to study the binding interaction of the anti-BSA/BSA immune complex in real-time. On a CM Dextran sensor chip, different amounts of BSA were simultaneously immobilized in four channels via amine coupling. Immobilization was performed using an automated graduated injection feature of the BI SPR software package, which requires only one sample injection for the entire graduated immobilization process making immobilization simple, accurate, and sparing on sample consumption. Channels 1 through 4 were immobilized with different amounts of BSA (in the order of decreasing density) and channel 5 was left bare for reference subtraction. The ability to test interactions using multiple BSA densities strengthens the data quality by helping to identify and minimize non-ideal or secondary binding effects. Seven sets of three anti-BSA concentrations (2.5, 5.0, and 10 nM) were repeatedly exposed serially in all five channels. A regeneration injection of 20mM NaOH followed each binding interaction in order to release the anti-BSA from the immobilized BSA and expedite further testing.
