Microbial Adhesion to Surfaces with Different Surface Charges

The adhesion behaviour of Streptococcus sanguis was studied on well-defined stearic and behenic acid multilayers which were prepared by depositing fatty acids on a solid substrate according to the Langmuir-Blodgett technique. Using this technique and by adjustment of the substrate pH it was possible to form outer surfaces consisting of either close-packed methyl or carboxyl end-groups. Thus adhesion was studied on non-polar surfaces formed by the methyl end-groups and on high density negatively charged surfaces formed by carboxyl groups. Under the experimental conditions the non-polar surfaces showed the same degree of adhesiveness as the reference (metal), whereas adhesion was completely inhibited on multilayers with a high negative surface charge. The significance of these results is discussed with regard to dental plaque formation.