Bacterial adhesion: From mechanism to control

Bacterial adhesion is the initial step in colonization and biofilm formation. Biofilms can, on the one hand, be detrimental to both human life and industrial processes, for example, causing infection, pathogen contamination, and slime formation, while on the other hand, be beneficial in environmental technologies and bioprocesses. For control and utilization of bacterial adhesion and biofilms, adhesion mechanisms must be elucidated. Conventional physicochemical approaches based on Lifshitz-van der Waals, electrostatic and acid–base interactions provide important models of bacterial adhesion but have a limited capacity to provide a complete understanding of the complex adhesion process of real bacterial cells. In conventional approaches, bacterial cells, whose surfaces are structurally and chemically heterogeneous, are often described from the viewpoint of their overall cellular properties. Cell appendages such as polysaccharide chains and proteinous nanofibers have an important function bridging between cells and the substratum in conventional adhesion models, but sometimes cause deviation from the models of cell adhesion. In reality, cell appendages are responsible for specific and nonspecific cell adhesion to biotic and abiotic surfaces. This paper reviews conventional physicochemical models and cell appendage-mediated cell adhesion. State-of-the-art technologies for controlling microbial adhesion and biofilm formation are also described. These technologies are based on the adhesion mechanisms.