Estimated force applied on platelet GpIbα*
| . | Radius 1 (a1), μm . | Radius 2 (a2), μm . | Separation distance (d), μm . | Shear stress, dyne/cm2 . | Peak force F, pN† . |
|---|---|---|---|---|---|
| GpIbα alone | 1.5 | 0.0045 | 0.035 | 100 | 0.085 |
| GpIbα with single VWF | 1.5 | 0.1 | 0.035 | 100 | 7.6 |
| GpIbα with self-associated VWF | 1.5 | 0.2 | 0.035 | 100 | 23.2 |
| GpIbα pulled by second platelet | 1.5 | 1.5 | 0.035 to 1 | 100 | 430 to 495 |
| GpIbα pulled by polystyrene bead | 1.5 | 3 | 2 | 16 |
| . | Radius 1 (a1), μm . | Radius 2 (a2), μm . | Separation distance (d), μm . | Shear stress, dyne/cm2 . | Peak force F, pN† . |
|---|---|---|---|---|---|
| GpIbα alone | 1.5 | 0.0045 | 0.035 | 100 | 0.085 |
| GpIbα with single VWF | 1.5 | 0.1 | 0.035 | 100 | 7.6 |
| GpIbα with self-associated VWF | 1.5 | 0.2 | 0.035 | 100 | 23.2 |
| GpIbα pulled by second platelet | 1.5 | 1.5 | 0.035 to 1 | 100 | 430 to 495 |
| GpIbα pulled by polystyrene bead | 1.5 | 3 | 2 | 16 |
The force applied between two spheres with radius a1 and a2 separated by a distance d was calculated.29 Applied shear stress is 100 dyne/cm2 (ie, shear rate = 10 000/s and medium viscosity = 1 cp) in all cases except for the case of platelet-bead interactions where shear stress was 2 dyne/cm2. Platelets are modeled as sphere with radius a1 = 1.5 μm. a2 and d are varied according to measured molecular dimensions of GpIbα, VWF, platelets, and hypothetical size of self-associated VWF.
In all cases, it is assumed that VWF or protein complex is bound to a single GpIbα receptor.