Investigating the composition and structure of the biofilm matrix is difficult because they are so complex. Despite this challenge, several key microscopy and biochemical assays have been developed and successfully used to look at biofilms more closely and determine what each component does.
Please see the brilliant ‘Images of microbiology’ activity book from the University of Dundee!
Using microscopy, it has been possible to demonstrate that biofilms have empty sections and multiple layers of interconnecting matrix and bacterial cells. As biofilms are complex structures, extra effort is needed to discriminate amongst the individual cells, the matrix, and the densely-sectioned components that most samples are comprised of.
More powerful microscopes and staining methods allow us to visualise the structures and individual components in three-dimensions. These structures include macromolecules, live cells, dead cells, what the matrix is composed of, and any extracellular DNA.
The empty, or less dense, thinner sections of biofilms may be a good target for interventions. Collecting microscopic evidence on how bacteria communicate and move nutrients around in biofilms would be an interesting study and provide further insight in how to control them.
For more microscope images of biofilms, please see our gallery.