Selective interaction between proteins and the outermost surface of polyelectrolyte multilayers: Influence of the polyanion type, pH and salt

Protein adsorption was studied by insitu ATR-FT-IR spectroscopy of consecut ively deposited polyelectrolyte multilayer systems terminated either with p oly(ethyleneimine) (PEI) or polyanions, such as poly(acrylic acid) (PAC), p oly(maleic acid-co-propylene) (PMA-P) or poly(vinyl sulfate) (PVS). The inf luence of the polyanion type, pH and ionic strength was investigated. Negat ively charged human serum albumin (HSA) was strongly repelled by multilayer s terminated with weak polyanions (PAC, PMA-P), whereas moderate attraction was observed for those terminated with the strong polyanion PVS. Changing the pH from 7.4 to 5 resulted in enhanced HSA adsorption onto PAC-terminate d multilayers. An increase in ionic strength diminished the attractive HSA adsorption onto PEI-terminated multilayers. For the PEI/PAC system, the bio medically relevant adsorption of human fibrinogen (FGN) is determined via i ts isoelectric point in accordance with three other proteins.