Shear fragility of human erythrocytes

Abstract

Shear breakage of human blood cells in saline solution has been studied under conditions of uniform shear, non-penetrating thickeners having been added merely to facilitate application of a sufficiently high stress using a conventional cone and plate apparatus. Cells in isotonic saline fragment and many micro spheres are formed. In hypotonic saline, haemolysis replaces fragmentation; few microspheres result. A shear stress threshold exists for haemolysis. The shear stress required to produce 50% haemolysis depends on the type of thickening additive; values of 2200 and 10,000 dyne cm⁻² are obtained for cells in Dextran and Methocel, respectively. Both microsphere formation and degree of haemolysis depend on the applied shear stress and the time of shearing.