JoVE Encyclopedia of Experiments
Microbiology
0 views • 3:23 min • February 26th, 2026
Take pathogenic bacteria-derived biofilms grown on nutrient agar.
The untreated biofilm features densely packed bacteria within a protective extracellular matrix.
The inhibitor-treated biofilm features loosely associated cells within a sparse matrix.
Bisect each biofilm, then expose one half to buffer as a control, and the other to ethanol to impose antimicrobial stress.
In the untreated, ethanol-exposed biofilm, the dense matrix reduces ethanol diffusion and limits cell penetration, resulting in less bacterial killing.
In the inhibitor-treated, ethanol-exposed biofilm, the sparse matrix permits ethanol to penetrate more easily, leading to greater bacterial killing.
Centrifuge the tubes and remove the supernatant. Add buffer and sonicate to disperse the cells.
Plate the diluted suspensions and incubate to allow the growth of viable bacteria.
Count colony-forming units (CFUs); fewer CFUs from the inhibitor-treated, ethanol-exposed biofilm confirm that matrix integrity is essential for ethanol resistance.
Take a clean razor blade and cut the biofilm colonies into two equal parts with the help of the template. Carefully lift one half of the colony with a clean spatula, and transfer it to a 1.5
View the full transcript and gain access to thousands of scientific videos