engleski

The Influence of the Conditions for Polyelectrolyte Multilayer Build-up on Bacterial Adhesion Capacity

It is well known that bacterial adhesion can be controlled by tailoring various material surface properties, such as surface charge, on which we concentrate in our study. We correlated the conditions at which the polyelectrolyte multilayers are formed (polyelectrolyte concentration, salt concentration), the number of polyelectrolyte layers, and the type of the terminating layer with corresponding bacterial adhesion. Additionally, we also investigated the adhesion of bacteria on protein-terminated polyelectrolyte multilayers. In our study we prepared poly(allylamine hydrochloride)/sodium poly(4-styrenesulfonate) (PAH/PSS) polyelectrolyte multilayers on silica surface. These synthetic polyelectrolytes have been widely used in the process of polyelectrolyte multilayer formation, and we also used them extensively in our investigations of polyelectrolyte complexes. Surface roughness and hydrophobicity of obtained polyelectrolyte multilayers were determined by atomic force microscopy and tensiometry. The surface charge was examined by the zeta potential measurements of silica particles covered with polyelectrolyte multilayers, whereby ionic strength and polyelectrolyte concentrations significantly influenced the build-up process. For adhesion experiments, we used the bacteria Pseudomonas aeruginosa and Escherichia Coli. The extent of adhered bacteria on the surface was determined by scanning electron microscopy. The results showed that the extent of adhered bacteria mostly depends on the type of terminating polyelectrolyte layer, since relatively low differences in surface roughness and hydrophobicity were obtained. In the case of polyelectrolyte multilayers terminating with a positively charged layer, bacterial adhesion was more pronounced than in the case when the polyelectrolyte layer was negatively charged.

Polyelectrolyte Multilayers, Bacterial Adhesion, Zeta-potential, Roughness, Hydrophobicity

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