Defining a Biofilm
A biofilm is a structured community of microorganisms, often bacteria, encapsulated within a self-produced polymeric matrix and attached to a surface. This matrix, primarily composed of exopolysaccharides, proteins, and DNA, provides structural integrity and protection for the microbial inhabitants.
Formation and Components
Biofilm formation typically begins with the reversible attachment of planktonic (free-floating) microorganisms to a surface. They then irreversibly attach, proliferate, and excrete the extracellular polymeric substance (EPS) matrix, which allows for adhesion, nutrient trapping, and protection. Different species can coexist within a single biofilm, forming complex, organized structures.
A Practical Example: Dental Plaque
A common and relatable example of a biofilm is dental plaque. This sticky, yellowish film forms on teeth when bacteria, primarily from your mouth, attach to the tooth surface and create an EPS matrix. If not removed regularly through brushing and flossing, plaque can lead to cavities and gum disease, demonstrating the impact of biofilms on health.
Importance and Applications
Biofilms are ubiquitous and have significant implications across various fields. In medicine, they are a major cause of chronic infections and antibiotic resistance, particularly on medical devices like catheters. Ecologically, they play crucial roles in nutrient cycling and bioremediation. Industrially, biofilms can cause biofouling in pipes and heat exchangers, but are also utilized in wastewater treatment and bioprocessing.