Contact activation of the plasma coagulation cascade. II. Protein adsorption to procoagulant surfaces

A study of blood protein adsorption to procoagulant surfaces utilizing a coagulation time assay, contact angles, Wilhelmy balance tensiometry, and electron spectroscopy (ESCA) is presented. Using a new contact angle method of measuring protein adsorption termed “adsorption mapping” it was demonstrated that protein‐adsorbent surfaces were inefficient activators of the intrinsic pathway of the plasma coagulation cascade whereas water‐wettable, protein‐repellent surfaces were efficient procoagulants. Repeated use of fully water‐wettable (spreading) glass procoagulants in the coagulation time assay demonstrated that putative “activating sites” were not consumed in the coagulation of platelet‐poor porcine plasma. Furthermore, these procoagulant surfaces retained water‐wettable surface properties after incubation with blood proteins and saline rinse. The interpretation of these observations was that plasma and serum proteins were not adsorbed to water‐wettable surfaces. However, ESCA of these same surfaces revealed the presence of a thin protein layer. Wilhelmy balance tensiometry resolved these seemingly divergent observations by demonstrating that protein was “associated” with a bound hydration layer, but not formally adsorbed through a surface dehydration or ionic interaction mechanism. © 1995 John Wiley & Sons, Inc.