Fig. 1.

Bacterial biofilm formation and development. During the complex process for biofilm formation, bacteria secret secondary metabolites, namely siderophores, to chelate iron (Fe) essential as a signal for biofilm development. Then, bacteria adhere to surfaces by adsorption and form a microcolony through the secretion of extracellular polymeric substances (EPS). In later stages, the biofilm is mature and densely populated due to the induction of the quorum sensing (QS) responsible for the regulation of genes involved in biofilm maturation and maintenance. Lastly, some bacteria start to detach and the biofilm disperses (adapted from Landini et al. [50] and Post et al. [10]).