Investigation of Polysaccharide Adsorption on Protein Conditioning Films by Attenuated Total Reflection Infrared Spectrometry.
The study of microorganisms at the aqueous/metal interface is of great interest as their presence is often associated with surface deterioration or corrosion. Surfaces submerged in aquatic environments rapidly become fouled with organic macromolecules, such as proteins and/or glycoproteins. Bacteria adhering to this conditioning film typically produce extracellular polysaccharides that anchor the cells to the substrate. In a previous paper, the kinetics of polysaccharide adsorption and desorption on protein conditioning films formed on bare germanium internal reflection elements (IREs) were investigated in an effort to gain a better understanding of the fouling process. This work has been extended to the study of adsorption phenomena at an aqueous/copper interface. Alginic acid and dextran were exposed to protein-conditioned and untreated copper films. In the absence of a protein biofilm, greater erosion of the Cu film was observed with flowing saline than with a solution of alginic acid in saline, and more Cu was removed at pH 4.8 than at pH 7.0. The neutral polysaccharide was less corrosive than alginic acid. The presence of a film of bovine serum albumin (13.5 nm) conditioning film did not shield the Cu film from the corrosive effects of either polysaccharide. In all experiments, as Cu slowly eroded from the surface of the IRE, metal islands formed leading to the observation of surface-enhanced infrared absorption (SEIRA). The intensity of the C-O stretching band of adsorbed dextran on Cu islands was over an order of magnitude greater than would be observed with a uniform Cu film of the same thickness. Enhancement of the amide II band of BSA was also observed. In general, the effect of SEIRA complicated spectral processing and interpretation and thus interfered with the determination of surface coverage and polysaccharide adsorption/desorption kinetics on protein conditioning films. Copyright 1999 Academic Press.
Ishida
KP
Department of Chemistry, University of Idaho, Moscow, Idaho, 83844-2343
Griffiths
PR