Peculiar behavior of blood at solid interfaces

Adsorption of proteins out of normal and afibrinogenemic blood plasma onto oxidized silicon crystal slices and glass was studied with the recording ellipsometer and by other means. Adsorbed matter was identified by its ability to adsorb specific antibody or to function in blood clotting. Our previous data suggest that fibrinogen as well as factor XII (the protein thought responsible for surface activation of clotting) are adsorbed first. If the plasma was not previously activated, it converts this fibrinogen, and then, in the presence of unactivated factor XII, it removes some. Both conversion and removal are retarded by previous activation of the plasma, or by lowering its concentration or temperature. Blood platelets (the elements that start thrombosis in vivo) adhere most to films on glass that contain unconverted fibrinogen. Present data suggest that plasma from a patient totally lacking plasma fibrinogen, had all properties of normal plasma when fibrinogen was added. Fibrinogen in bulk or pre-adsorbed state neither helped nor hindered adsorption of factor XII activity. After prolonged contact of normal plasma with an activating interface, adsorbed fibrinogen could be recovered by elution. Readsorption was then followed by reconversion.