Effect of preincubation of vWF solution with the collagen-coated surface. Collagen-coated glass slides were preincubated with vWF solution (50 μg/mL) at 4°C overnight, and adhesion was measured under the shear rates of 200, 800, and 3,200/s (○). As controls, platelet adhesion on collagen- (▪) and vWF-coated (▴) surfaces was also measured.