Illustration of research being carried out into vWF, a glycoprotein found in blood plasma. The protein is attached to two beads, one (grey sphere) held by a pipette tip (left), the other (blue sphere) attached to the protein’s platelet receptor and held and controlled by a laser. The protein binds to collagen exposed in damaged epithelial cells. This produces a change in the shape of the protein that starts a cascade of signals that begin the clotting process.