Characterization of VWF fragments. (A) Surface plasmon resonance (SPR) analysis of rhFVIII binding to PL monolayer in the presence of fl-VWF, VWF-12, VWF-13, or bovine serum albumin (BSA). Molar ratios are given in the table below the figure. (B) VWF:GPIbM assay of fl-VWF in the presence of increasing concentrations of VWF-12, human serum albumin (HSA), or VWF-12 alone. Concentrations in nanomoles per liter are shown in the table below the figure. (C) Collagen binding of washed human platelets under flow in the absence or presence of VWF with increasing concentrations of VWF-12. Mean ± standard deviation (SD) shown in all panels.