VWF oxidation enhances its platelet-binding function. (A) Ristocetin-induced platelet agglutination using unoxidized VWF or VWF oxidized in the presence of shear stress. The VWF was mixed with lyophilized platelets in the presence of ristocetin (0.25 mg/mL), and platelet agglutination was monitored by light transmission in a platelet aggregometer. (B) Comparison of VWF oxidized under static or shear conditions for their ability to agglutinate platelets. (C) Binding of nanobody AU/VWFa-11, which detects a gain-of-function conformation in the VWF A1 domain, as detected by ELISA. The results represent the means ± SD of 3 experiments.