Dynamics of platelet adhesion to artificial materials and cultured endothelial cells under shear flow

To evaluate the dynamic features of platelet adhesion to biomedical materials, a new shear flow testing apparatus was constructed. A cone-plate rotational viscometer, equipped with a transparent cone and transparent bottom window, was mounted on the stage of an inverted microscope. Test materials (glass, silicone, polyvinyl chloride, Thermanox, and porcine endothelial cells cultured on glass coverslips) were placed on the bottom window. Real time microscopic images of platelets adherent to the test materials in a shear rate range between 3.6 and 360 1/s were observed and recorded with a videocassette recorder. Time course changes in the number of adherent platelets were analyzed on the basis of a convective diffusion model. With respect to effective diffusivity of platelets (De) and the surface reactivity constant (K), less significant differences were found among artificial materials. In the case of cultured endothelial cells, both De and K, which were evaluated for the first time in the present study, were two to four orders of magnitude lower than those obtained with artificial materials.