Stagnant versus dynamic conditions: a comparative adsorption study of blood proteins

Haemodynamic parameters of flowing blood, such as diffusion, convection, flow and shear rates, are important as they determine the interaction of cells with vessel walls and prosthetic implants in the cardiovascular system. Most of the studies under flow conditions have been performed with platelets or other cells, and less attention has been paid to the effects that these parameters may cause on the adsorption of proteins. For this reason we studied how different shear rates affect the adsorption of human albumin, fibrinogen, total serum proteins, and complement factors 1q and 3c from human serum to silicon surfaces. The most relevant results indicate that during non-flow conditions the amount of adsorbed proteins is always lower than under flow. The different shear rates (225, 915, 1800 and 2700 s(-1)) all gave similar results, indicating that such a parameter is not very critical for single protein deposition. The differences in kinetics of complex protein solutions are conveniently highlighted by use of specific polyclonal antibodies. The difference between non-flow or low shear rate conditions and physiological flow conditions was enhanced for the complement cascade system.