Ellipsometric observations of surface adsorption and molecular interactions of native and modified fibrinogen and factor VIII

Abstract The adsorption of native and modified factor VIII and of fibrinogen on gold surfaces has been evaluated by ellipsometiy. Fibrinogen and commercial factor VIII concentrate were adsorbed at similar rates after diffusion in buffered saline at 21°C, and the measured mean thicknesses of the monolayers were 17.3 and 17.4 A respectively. Treatment of factor VIII with CaCl 2 (0.25 M) reduced the measured film thickness by 4 A, and reduction of fibrinogen to α,β and γ chains was associated with a 7.7 A loss of film thickness. Thrombin appeared to bind to fibrinogen and stage 1 plasmin digests, but not to stage 2 or 3 digests.