PROTEIN ADSORPTION STUDIES ON STANDARD POLYMERIC MATERIALS

Adsorption of fibrinogen from buffer as a single protein and from plas ma to four materials has been studied. The two NIH-NHLBI primary refer ence standards, filler free polydimethylsiloxane and low density polye thylene, were used along with polyvinylchloride and cellulose material s supplied by the IUPAC Working Party. The materials were examined in both film and tubing form, except for polydimethylsiloxane which was s tudied only in tubing form. Adsorption was measured at room temperatur e using I-125-labelled fibrinogen. The order of adsorbed amounts in th e single protein experiments was found to be: cellulose < PVC < PE = P DMS. Apparent adsorption affinities are in the same order. In plasma, all surfaces except cellulose showed maxima in adsorption as a functio n of plasma concentration after 5 min contact. This is indicative of i nitial adsorption followed by displacement of fibrinogen (the Vroman e ffect). Cellulose showed very low adsorption of fibrinogen from plasma . The Vroman maxima were more pronounced on the tubing samples than on the films, and, as for the single protein experiments, adsorption was found to be less on tubing than on film samples. A tentative interpre tation of the Vroman effect data suggests that the order of procoagula nt activity of the materials may be: PDMS = PE < PVC < cellulose.