Procoagulant activity of surface-immobilized Hageman factor. Journal   Biomaterials. Citation   Biomaterials. 27(33):5643-50 Publication date   2006 Nov Authors   Chatterjee K Vogler EA Siedlecki CA Investigators   Christopher Siedlecki Erwin Vogler Grant agencies   National Heart, Lung, and Blood Institute Grants   NHLBI R01 HL69965 MeSH headings   Blood Coagulation Coagulants Enzymes, Immobilized Factor XII MeSH qualifiers   physiology metabolism Abstract   Procoagulant activity of surface-immobilized coagulation factor XIIa (activated Hageman factor) is reported. Activity of FXIIa immobilized onto the surfaces of three silanized-glass procoagulants spanning a wide range of wettability was assayed in normal and FXII-deficient plasmas. Previously published mathematical models were used to characterize the procoagulant activity of protein-immobilized materials and soluble enzymes. Results show that FXIIa activity is unrelated to underlying procoagulant surface chemistry and is similar to soluble FXIIa activity. The uninfluential role of the surface on FXIIa suggests that the solid surface activates FXII in biomaterial-induced blood coagulation but is not otherwise involved in FXIIa activity as described by the classical mechanism.