THE INITIAL REACTIONS OF GRAPHITE AND GOLD WITH BLOOD

The initial reactions of graphite and gold with blood were investigate d by short-time exposure to capillary blood and detection of surface-a dsorbed plasma proteins and cells with an immunofluorescence technique . Antibodies specific to fibrinogen, complement factors Clq and C3c, p rothrombin/thrombin, von Willebrand factor, and platelet- and leukocyt e-membrane antigens were used. The fluorescence intensity was quantita ted by computer-aided image analysis. Fibrinogen was the most abundant plasma protein immobilized on either surface, and dense populations o f platelets adhered to the protein layer. Complement factors and proth rombin/thrombin were found on the graphite surface, localized in fibri n clots or related to platelets. Platelets were activated (expression of selectin CD62) on both surfaces but more extensively so on the Sold surface. Activation of polymorphonuclear granulocytes (PMNGs), measur ed as expression of integrin CD11b, was seen on both surfaces but with different kinetics. On the graphite surface, the CD11b expression was only transient whereas on gold it increased with time. Our data indic ate that graphite is more thrombogenic than gold but less inflammatory . (C) 1997 John Wiley & Sons, Inc.