Sequential adsorption of human serum albumin (HSA), immunoglobulin G (IgG), and fibrinogen (Fgn) at HMDSO plasma polymer surfaces

The sequential adsorption of human serum albumin (HSA), immunoglobulin G (IgG), and fibrinogen (Fgn) at hexamethyldisiloxane (HMDSO) plasma polymer surfaces was investigated with ellipsometry and total internal reflection fluorescence spectroscopy (TIRF) as a function of adsorption time, pH, and excess electrolyte concentration. HSA was found to self-exchange very slowly (approximate to hours) at pH 7.2, irrespective of adsorption time in the range 90 s to 90 min. Preadsorbed HSA was exchanged by Fgn and IgG only to a limited extent irrespectively of pH (5 less than or equal to pH less than or equal to 8) and excess electrolyte concentration (5 mM less than or equal to C-s less than or equal to 150 mM). At an excess electrolyte concentration of 150 mM, the sequential adsorption of Fgn and IgG was dramatically reduced by HSA preadsorption, irrespective of pH. At an excess electrolyte concentration of 5 mM on the other hand, there were indications of second-layer adsorption of Fgn and IgG. (C) 1997 Academic Press.