Fig 2: Quantitative morphologic characterization of von Willebrand factor (VWF)-A1–DNA complexes by AFM. VWF-A1 at the indicated concentrations was incubated with DNA for 3 hours and imaged by AFM. (A–B) Analysis of DNA molecules alone: the distributions of DNA length (A) and spot number. (C–E) Analysis of VWF-A1–DNA complexes at 10 nM: the distributions of DNA length (C), spot number (D), and spot location (E). (F–H) Analysis of VWF-A1–DNA complexes at 100 nM: the distributions of DNA length (F), spot number (G), and spot location (H).

Fig 3: von Willebrand factor (VWF)-A2 increases the contour length of VWF-A1–DNA complexes. (A) Representative force-extension curves of DNA measured in phosphate-buffered saline (PBS) (black), 500 nM VWF-A1 (green), 500 nM VWF-A1 preincubated with 10 nM VWF-A2 (violet), 100 nM VWF-A2 (cyan), or 500 nM VWF-A2 (blue). Curves were fitted to the extensible worm-like chain (WLC) model (red). (B) DNA contour length as a function of different VWF-A1 and VWF-A2 concentrations (n > 130 for each group). (C) Representative force-extension curves of DNA measured in PBS (black) and in the presence of 10 nM (green), 100 nM (blue), and 500 nM VWF-A1A2 solution (cyan). Curves were fitted to the extensible WLC model (red). (D) DNA contour length as a function of VWF-A1A2 concentration (n > 60 for each group). Statistical significance was assessed using 1-way ANOVA followed by Bonferroni’s post hoc test. Significant levels: ∗, P < .05; ∗∗, P < .01; ∗∗∗, P < .001; ∗∗∗∗, P < .0001.

Fig 4: DNA and platelet adhesion to A1-functionalized surfaces under flow in the absence or presence of von Willebrand factor (VWF)-A2. (A) Representative time-integrated images of firmly adhered DNA (green) on substrates coated with PBS containing 1% BSA (control), 3000 nM VWF-A1, or 3000 nM VWF-A1 preincubated with 3000 nM VWF-A2, or 3000 nM VWF-A1A2 after perfusion of DNA (15 μg/mL) for 2 minutes at the indicated shear stresses. (B) Quantification of DNA fluorescence intensity under each condition. (C) Representative time-integrated images of firmly adhered platelets (red) under the same substrate conditions after perfusion of platelets (4 × 107 cells/mL) for 2 minutes at the indicated shear stresses. (D) Quantification of firmly adhered platelets under each condition. (E) Representative time-integrated images of firmly adhered DNA (green) and platelets (red) after perfusion of a DNA–platelet mixture (15 μg/mL DNA; 4 × 107 cells/mL platelets) for 2 minutes at the indicated shear stresses. (F) Quantification of firmly adhered platelets in the presence of DNA. Scale bar: 50 μm. Data represent the mean ± SEM from 3 independent experiments. Statistical significance was determined by 2-way ANOVA followed by Tukey’s post hoc test. Significance levels: ∗, P < .05; ∗∗, P < .01; ∗∗∗, P < .001; ∗∗∗∗, P < .0001.

Fig 5: Representative AFM images of von Willebrand factor (VWF)-A1–DNA complexes. VWF-A1 at the indicated concentrations was incubated with DNA for 3 hours and imaged by AFM. (A) Representative image of VWF-A1–DNA complexes at 10 nM. (B–C) Representative image of VWF-A1–DNA complexes at 100 nM. Scale bar: 100 nm.