Adhesive Forces between A1 Domain of von Willebrand Factor and N-terminus Domain of Glycoprotein Ibα Measured by Atomic Force Microscopy

Aim: von Willebrand factor (VWF) plays an important role in the regulation of hemostasis and thrombosis formation, particularly under a high shear rate. However, the adhesive force due to the molecular interaction between VWF and glycoprotein Ib alpha (GPIb alpha) has not been fully explored. Thus, we employed atomic force microscopy to directly measure the adhesive force between VWF and GPIb alpha. Methods: We measured the adhesive force between VWF and GPIb alpha at the molecular level using an atomic force microscope (AFM). An AFM cantilever was coated with recombinant N-terminus VWF binding site of GPIb alpha, whereas a cover glass was coated with native VWF. Results: The adhesive force at the molecular level was measured using an AFM. In the presence of 1 mu g/mL VWF, the adhesion force was nearly 200 pN. As per the Gaussian fit analysis, the adhesive force of a single bond could have been 54 or 107 pN. Conclusion: Our consideration with the Gaussian fit analysis proposed that the adhesive force of a single bond could be 54 pN, which is very close to that obtained by optical tweezers (50 pN).