Polysaccharides and sticky membrane surfaces: critical ionic effects

By measuring the adhesion (using Atomic Force Microscopy, AFM) between a series polymer substrates of different surface energies and an extracellular polysaccharide (EPS) secreted by Pseudomonas atlantica, we show that the ionic strength of the aqueous solution critically determines their mutual adhesion. The results presented here demonstrate that, under physiological and marine conditions, critical surface tension correlates with adhesion, and that during synthetic membrane filtration with solutions containing biological molecules, such as polysaccharides, proteins and nucleic acids at relatively low ionic strength, wettability correlates inversely with adhesion (fouling).