Effect of surface hydrophobicity on the adhesion of S. cerevisiae onto modified surfaces by poly(styrene-ran-sulfonic acid) random copolymers.

The hydrophobicity of solid surfaces has been regarded as a controlling factor in microbial adhesion phenomena. In this study, the surface hydrophobicity was modified by coating with a poly(styrene-ran-sulfonic acid) random copolymer (PS-x-SA, charge density (x): 0-15.3%), and the adhesion rate, J0, of S. cerevisiae performed with a direct observation technique. The results indicated that the degree of sulfonation of PS-x-SA greatly influenced the hydrophobicity of substrates and the adhesion of yeast cells. The J0 of PS-x-SA substrates were gradually decreased as increasing charge density. The interactions between cells and substrates explained by the XDLVO theory, predicted that the decrease of J0 as increasing charge density was not due to the increase of electric double layer repulsion, but mainly due to the hydrophobic acid-base interactions. Also, it predicted that microbial adhesions of PS-x-SA were mostly reversible, while some of PS and PS-5.1-SA adhered cells were hardly removed. Based on these results, XDLVO theory was effective for predicting adhesion phenomena of S. cerevisiae onto the PS-x-SA-coated substrates.