The adhesion of neutrophils on a biomaterial surface depends on the surface chemistry of the material and the cell, as well as the composition and conformation of adsorbed protein and the adherence of other cells when the biomaterial is exposed to circulating blood. In this study, HK and HKa were allowed to adsorb on three different polyurethanes: underivatized (PU-base), quatemized (PU-NR4), sulfonated (PU-SO3). The effect of kininogen adsorption on the degree of neutrophil adhesion was examined. The surface density of the adsorbed protein was also investigated. The PU-NR4 surface adsorbed the most HK and HKa and had the high degree of neutrophil adhesion. Although the surface density of adsorbed HK and HKa on the PU-SO3 surface, the degree of neutrophil on adhesion was significantly lower when compared to the PLT-NR4 and PU-base surfaces. HK and HKa contain binding sites for both anionic surfaces and neutrophils in the same domain (D-5H). When adsorbed to the anionic PU-SO3 surfaces, HK and HKa did not have the neutrophil binding sites available and therefore, exhibited an anti-adhesive effect. In contrast, the neutrophil binding domains D-3 and D-5H of adsorbed kininogens were available on the PU-NR4 and PU-base surfaces. Thus, adsorbed kininogens on these two surfaces lost their anti-adhesive property and this led to a high degree of neutrophil adhesion. (C) 1999 Elsevier Science B.V. All rights reserved.