Analysis of the interaction of fibrinogen with fibrin by SPR. (A) Representative profiles of the SPR responses (RU) for fibrinogen concentrations ranging from 0.1 μM to 11 μM binding to fibrin coupled to the chip surface. Fibrin was prepared by coupling of intact fibrinogen to the chip followed by its activation with thrombin and inactivation of thrombin with PPACK as described in “Materials and methods.” RU indicates response units. (B) Saturable binding curve. Req is the response at equilibrium.