INVESTIGATION OF MUSSEL ADHESIVE PROTEIN ADSORPTION ON POLYSTYRENE AND POLY(OCTADECYL METHACRYLATE) USING ANGLE-DEPENDENT XPS, ATR-FTIR, AND AFM

The irreversible adsorption of mussel adhesive proteins (MAP) from the marine mussel Mytilus edulis has been investigated on polystyrene (PS ) and poly(octadecyl methacrylate) (POMA) surfaces using angle resolve d X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometry, and atomic force m icroscopy (AFM), Angle resolved XPS was used to quantify the elemental composition with depth of the upper 90 Angstrom of the surface, and A FM was used to obtain the surface topography, The adsorption pattern o f MAP, revealed by AFM images, is distinctly different on the two poly mer surfaces and suggests that the substratum influences protein adhes ion, The depth profiles of MAP, obtained from angle resolved XPS, show differences in nitrogen composition with depth for MAP adsorbed to PS and POMA, Infrared spectra of hydrated adsorbed MAP revealed signific ant differences in the amide III region and in two bands which may ori ginate from residues in the tandemly repeated sequences of MAP, This d ata demonstrates that the chemistry of the polymer film that is presen t at the protein-polymer interface can influence protein-protein and p rotein-surface interactions. (C) 1996 Academic Press, Inc.