Rheological discrimination between native, rigid and aggregated red blood cells in oscillatory flow

The viscoelastic behaviour of hardened or aggregated red blood cells is compared with the flow pattern of native red blood cells, all suspended in buffer solution at a hematocrit of 45%. The rheological properties are investigated under oscillatory shear at the constant frequency of 2Hz. Variation of the amplitude covers a range of shear-rates from 0.5/s to 200/s. It can be seen that rigidification of the red cells by treatment with glutardialdehyde leads to changes of the flow properties in the range of shear-rates above 10/s, whereas aggregate formation due to addition of dextran distinctly alters the flow properties in the range of shear-rates below 10/s.