The role of intermolecular interactions: studies on model systems for bacterial biofilms

The mechanical stability of biofilms and other microbial aggregates is of g reat importance for both the maintenance of biofilm processes and the remov al of undesired biofilms. The binding forces are weak interactions such as London dispersion forces, electrostatic interactions and hydrogen bonds. In a first attempt to rank their contribution, the viscosity of solutions of extracellular polymeric substances (EPs) from a mucoid strain of Pseudomona s aeruginosa is measured. In order to distinguish the binding forces, subst ances are chosen which individually address the different types of bonds. P olyacrylic acid is identified as a suitable model system for EPS when molec ular interactions are studied. Electrostatic interactions and hydrogen bond s are found to be the dominating forces among macromolecules within the bio film. (C) 1999 Elsevier Science B.V. All rights reserved.