Examiner

Biofilms are communities of sessile microorganisms attached to a surface and imbedded in a matrix of extracellular polysaccharide substances. These communities can be found in diverse aquatic environments, such as in industrial pipes and in humans. By forming microcolony structures, which are highly resistant to adverse physical conditions as well as antimicrobial agents, biofilms are very problematic when associated with e.g. persistent infections. In order to find new ways of controlling biofilm growth, the processes involved in biofilm development must be investigated further. The main interest of this study is the occurrence of void formation inside biofilms. This phenomenon has been observed in several studies and has been correlated to cell death inside the microcolonies. The occurrence of cell death has recently been associated with the presence of nitric oxide in the biofilm. In this study, the implications of nitric oxide accumulation on biofilm development were investigated using an individual-based model. Specifically, the role of nitric oxide in void formation was considered. A large number of simulations were run using different parameter settings in order to determine i