STRUCTURAL-CHANGES OF BOVINE SERUM-ALBUMIN UPON ADSORPTION TO MODIFIED FLUOROPOLYMER SUBSTRATES USED FOR NEURAL CELL ATTACHMENT STUDIES

In this work, we report changes in steady-state fluorescence spectra f or dansylated bovine serum albumin (BSA) on its adsorption to a series of modified poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) su rfaces. Specifically, dansylated BSA (BSA-Dan) is adsorbed to unmodifi ed FEP, radio frequency glow discharge plasma modified FEP (resulting in an hydroxylated surface, FEP-OH), and FEP-OH that is subsequently t reated with gamma-(aminopropyl)triethoxysilane (resulting in an aminat ed surface). The emission spectra of the most strongly adsorbed BSA-Da n is red shifted (>45 nm) relative to native BSA-Dan. The emission spe ctrum of BSA-Dan adsorbed on amine-modified FEP is red shifted by an a dditional 15 nm relative to BSA-Dan adsorbed on unmodified FEP. These results suggest that the microenvironment surrounding the dansyl repor ter group is altered significantly on BSA adsorption and the microenvi ronments are different for BSA-Dan adsorbed to the various FEP-based s urfaces. The emission spectrum of BSA-Dan adsorbed to the amine-modifi ed FEP surface resembled that of chemically denatured BSA-Dan on unmod ified FEP. This is consistent with adsorption leading to a conformatio nal change that is similar to the one induced by chemical denaturation . These results, suggesting conformational changes in the adsorbed BSA , provide insight into our previously published results showing select ive cellular attachment of mouse neuroblastoma cells (NB2a) and rat en dothelial cells onto the amine-modified FEP only in the presence of ad sorbed BSA (J. Biomed. Mater. Res. 1993, 27, 917).