The Influence of Red Cell Mechanical Properties on Flow Through Single Capillary-Sized Pores

Abstract

The resistive pulse technique was used to study the influence of specific mechanical properties of the red cell on its ability to enter and flow through single capillary-sized pores with diameters of 3.6, 5.0 and 6.3 μm and lengths of 11 μm. A two-fold increase in membrane shear elasticity resulted in a 40 percent increase in the cell’s transit time through a 3.6 μm pore but produced no change in transit time through a 6.3 μm pore. A two-fold increase in membrane shear viscosity produced a 40 percent increase in transit time through the 3.6 μm pore and small but significant increases in transit times through the larger pores. Osmotically dehydrated cells showed no increase in transit time through a 6.3 μm pore, but showed increases in transit times of 50 to 70 percent through 5.0 and 3.6 μm pores. Dense red cells showed increased transit times through both 5.0 μm and 6.0 μm pores. These results indicate that for cells with normal geometric properties, the membrane’s shear viscosity and elasticity only influence the cell’s transit through pores of 5 μm or less in diameter. However, alterations in the cell’s geometric properties can extend the influence of membrane shear properties to larger diameter pores.