USING ELISA TO EVALUATE COMPLEMENT ACTIVATION BY REFERENCE BIOMATERIALS

The interaction between blood and an artificial surface results in the activation of complement and can lead to extensive inflammatory react ions. In vitro work was undertaken to validate a system of assays to e valuate the complement activation of a candidate biomaterial by compar ing its capacity of activation with that of reference biomaterials. Th e biomaterials tested were cellulose acetate, cellulose dialysis tubin g, low density polyethylene, polydimethylsiloxane and AN69. Complement activation was assessed using ELISA for iC3b, C3a and Factor Bb. Resu lts showed that (1) iC3b measurements may underestimate complement act ivation, (2) the presence of Bb in plasma or serum was a reliable indi cator of complement activation, (3) measurements of C3a are of interes t but are difficult, (4) adsorption or/and binding of complement prote ins occured on the surface. Evaluation of complement activation for a biomaterial should include the assessment of the fluid phase (in serum or plasma) as well as the bound phase (on the surface of the biomater ial) of complement.