Flow-dependent platelet behaviour in blood-material interactions

Platelet activation and adhesion are important parameters characterizing blood compatibility of biomaterials. A platelet transport theory based on convection diffusion, which describes the influence of wall shear rate, platelet concentration, axial position, hematocrit and red cell size, was originally proposed by Turitto and Baumgartner and later expanded by Aarts. This theory was applied in an in vitro perfusion system for three different materials with wall shear rates between 100 s(-1) and 4300 s(-1) in order to cover the regions of diffusion controlled, reaction controlled and intermediate platelet adherence. Platelet diffusivity a nd platelet vessel wall surface reactivity were determined for these cases and the constants m and n were calculated using the relation between platelet diffusivity and shear rate as expressed by the following power law function: D-w = m*gamma(w)(n).