Figure 1.

SPR results at a fixed angle. (a) The change of SPR intensity when the casein solution was flowed across the gold surface, and followed by 1 mM PLA solution. (b) Control experiment showing little change of final SPR intensity when PLA was flowed across the gold surface. The gold film was first exposed to buffer (B), then casein (CS) or PLA solution. Arrows indicate the times when the solutions were changed.