ADSORPTION OF FIBRINOGEN AND SOME OTHER PROTEINS FROM BLOOD-PLASMA ATA VARIETY OF SOLID-SURFACES

Enzyme linked immunosorbent assay (ELISA) was used for the estimation of protein adsorption from blood plasma at some model solid surfaces. The majority of those surfaces were made in the wells of microtiterpla tes of polystyrene commonly used for ELISA purposes. Three of the mode l surfaces were made by radio frequency plasma discharge polymerizatio n (RFPD) of the microtiterplates of polystyrene. The monomers we used were diaminocyclohexane, hexamethylenedisiloxane, and acrylic acid. Ot her surfaces investigated were: unmodified polystyrene, oxidized polys tyrene, hydrophilic silicon oxide, and methylized silicon oxide. Two s ubstances, Tween and bovine serum albumin (BSA), for the prevention of unintended adsorption of ELISA conjugate were also tested and the BSA method was found to be superior for this kind of investigation. Human blood plasma at different dilutions was incubated in the surface-modi fied microtiterplates followed by incubation of rabbit antibodies agai nst fibrinogen (FG), fibronectin (FN), human serum albumin (HSA), comp lement factor 3 (C-3), and immunoglobulin G (IgG). Visualization of bo und antibodies was then made by standard ELISA procedure. At low blood plasma concentrations (plasma dil 1/1000), anti-IgG and anti-HSA were detected at high levels at the majority of surfaces. At high blood pl asma concentration (plasma dil 1/10), anti-FG dominated at most surfac es. ELISA activity of FN and C-3 were low at most of the surfaces at b oth plasma concentrations. An 'optimum' plasma dilution for the detect ion of surface bound FG (the Vroman effect) was not found with the use of the ELISA on any of the surfaces except for the silicon oxide surf ace. This is in contrast to findings by others who had used isotope-la belled fibronogen diluted in plasma. However, 'false' Vroman effects o ccured if nonionic surfactant was used for the prevention of unspecifi c binding in the ELISA.