Mechanical degradation of polyacrylamide solutions as a model for flow induced blood damage in artificial organs

Human or animal blood is normally used as a test fluid for the in vitro eva luation of hemolysis by artificial organs. However, blood has some disadvan tages (large biological variability and problems with cleaning the devices) . For that reason, we searched for a reproducible technical fluid with bloo d-like flow characteristics that exhibits similar shear depending destructi on. In this study, a direct comparison between erythrocyte damage of bovine blood and shear-induced degradation of polyacrylamide solution is given. A uniform shear field was applied to the fluids using a shear device with a plate-plate geometry. It was shown that similarities exist between erythrocytes disaggregation an d breakdown of super molecular structures in polymer solutions, caused by m echanical stress. In both cases steady low shear viscositity was diminished and the elastic component of complex viscosity of blood and polymer soluti ons has been reduced. There is a correlation between shear-induced hemolysi s of bovine blood and mechanical polymer-degradation, which depends on the applied shear stresses.