| Summary: | In this study, three different methods have been used to investigate the bacterial interaction with the substratum, i.e. atomic force microscopy (AFM), spinning disc and micromanipulation. Pseudomonas fluorescens NCIMB 9046 was chosen as a model microorganism to study the cell-substrate adhesion. By having three different colloidal particles: stainless steel (Grade 304), glass and cellulose, the force measurements were performed in growth medium and ambient air using AFM. The results demonstrated that the adhesive forces were influenced by the surface hydrophobicity, electrostatic, van der Waals and steric interactions. In ambient air, the capillary force played an important role. The effect of shear forces on the bacterial adhesion was further examined. By using an apparatus of spinning disc, the cell removal was strongly influenced by the spinning time, angular velocity and surface hydrophobicity. Finally, the adhesive and cohesive strengths of biofilms were examined via a micromanipulation technique. Results indicate that with pH7 and low initial glucose concentration (0.25% (w/v)) the biofilm adhesion was the greatest among the conditions investigated. The cohesive strength of biofilm was found to depend on on the distance between the force probe and the substrate surface.
|
|---|
