Mass Transport and Chemical Kinetics of Platelot Adhesion to Biomaterials

Abstract

<p>The operating procedure for Couette flow apparatus capable of evaluating the thromboresistance (by examination of platelet adhesion) of materials was standardized. It was established that operating at room temperature instead of at the normal physiological temperature, 37°C, did not affect platelet adhesion and that a continued exposure to a shear rate of 19 secֿ¹ for 40 minutes did not damage the platelets. The radioisotope evaluation technique gave consistent results with the direct counting method.</p> <p>Platelet diffusivity in the presence of red cells was found to be one or two orders of magnitude greater than the one predicted by Brownian motion and to be dependent on shear rate and hematocrit.</p> <p>A theoretical model for platelet adhesion was developed for the diffusion limited case and described the experimental data for collagen coated glass.</p> <p>Glass, polystyrene, sulphonated polystyrene and polyurethane reached equilibrium values of platelet adhesion after 2-10 minutes. The equilibrium values of these surfaces were not distinguishable. Albumin coated glass reached an equilibrium value in less than 2 minutes that was substantially lower than the other surfaces investigated. Platelet adhesion to collagen, as predicted by the diffusional model, continued to increase with time.</p>