ADSORPTION OF COAGULATION PROTEINS FROM WHOLE-BLOOD ON TO POLYMER MATERIALS - RELATION TO PLATELET ACTIVATION

A combination of methods, immunoassays of plasma proteins and platelet release of beta-thromboglobulin and chromogenic substrates for enzymatically active coagulation factors, was used to measure the reactions of coagulation proteins upon contact between whole blood and artificial surfaces as a function of time and surface material. Four types of well-known polymer surfaces, polyvinylchloride, polytetrafluoroethylene, polyurethane and silicone rubber, were investigated to elucidate if a simple and fast in vitro experimental set-up can be of guidance in the selection of materials for use in vivo. Platelets were activated at the polymer surfaces whereas the coagulation enzymes showed little activity on the polymer surfaces tested. There was a correlation between the adsorption of adhesins (fibrinogen, fibronectin and factor VIII-related antigen) at the surfaces and the release of beta-thromboglobulin from platelets, suggesting that adsorption of adhesins is a major determinant of blood compatibility of polymer materials. Significant differences between the surfaces were seen - polyurethane being the surface with the least protein adsorbed and least platelet activation initiated. This study shows that it is possible to make a first in vitro choice of possible blood compatible artificial surfaces before expensive and cumbersome in vivo experiments.