Active layer dynamics drives a transition to biofilm fingering

Area of Science:

• Biofilm biophysics
• Microbiology
• Cellular organization

Background:

• Biofilm growth can result in smooth or rough interface morphologies.
• This 'fingering' transition is linked to the active layer of cells at the biofilm interface.
• The balance between nutrient supply and microbial growth influences biofilm morphology.

Purpose of the Study:

• To investigate the driving factors behind the biofilm-fingering transition.
• To understand the role of the active layer in biofilm morphology.
• To explore the dynamics of spatial organization in biofilm development.

Main Methods:

• Long-time individual-based simulations of growing biofilms.
• Analysis of dynamical changes within the active cell layer.
• Construction of a phase diagram for the fingering transition.

Main Results:

• The biofilm-fingering transition is associated with dynamical changes in the active layer.
• Gaps forming in the active layer lead to interface pinning.
• Pinning can be transient or permanent, resulting in diverse biofilm morphologies.
• The magnitude of relative fluctuations in active layer thickness controls the transition.

Conclusions:

• Active layer dynamics play a central role in controlling biofilm interface pinning.
• Relative fluctuations in active layer thickness, not thickness per se, are the key factor.
• Understanding these dynamics is crucial for predicting and controlling biofilm morphology.