Biofilm mechanics

When bacteria form a biofilm, the bacteria create a matrix of extracellular polymeric substances. In the case of P. aeruginosa, the main polymer components of the biofilm matrix are the extracellular polysaccharides Pel, Psl, and alginate, and extracellular DNA.

Shown above is a biofilm whose mechanics have just been measured on a rheometer.

We have recently shown that in patients with cystic fibrosis who can be infected with biofilms for decades, the biofilm-forming bacteria in the body evolve to change their production of extracellular matrix polymers in a way that promotes mechanical toughness.

Now, we are investigating two questions:  (1) what are the benefits from mechanical toughness that help biofilm infections?  and (2) how can we develop treatments that disrupt mechanical properties to weaken the biofilm and make it easier to clear or minimize?

For (1), we are examining how neutrophils are impacted by biofilm mechanics.  Neutrophils (shown above) are phagocytic immune cells that try, and usually fail, to clear biofilm infections.

For (2), we are trying enzymatic approaches to disrupting specific matrix components.  Because different matrix materials contribute different mechanics to the biofilm, we expect to find ways to reduce key aspects of biofilm mechanics to make them more easily cleared by neutrophils.