Surface thermodynamics of bacterial adhesion

Area of Science:

• Microbiology
• Surface Chemistry
• Biophysics

Background:

• Bacterial adhesion to surfaces is a critical factor in biofilm formation and infection.
• Understanding the thermodynamic principles governing bacterial adhesion is essential for controlling microbial contamination.
• Previous models have explored particle adhesion, but empirical validation with diverse bacterial strains and polymeric surfaces is needed.

Purpose of the Study:

• To investigate the adhesion of five bacterial strains (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Listeria monocytogenes) to various polymeric surfaces.
• To validate a thermodynamic model predicting bacterial adhesion based on surface tension interactions.
• To utilize adhesion data for determining the surface tension of different bacterial species.

Main Methods:

• Bacterial suspensions (10^8 cells/ml) were incubated with polymeric surfaces (Teflon, polyethylene, polystyrene, acetal, sulfonated polystyrene) for 30 minutes at 20°C.
• The surface tension of the suspending medium (Hanks balanced salt solution) was modified using dimethyl sulfoxide.
• Adhered bacteria were quantified using image analysis after rinsing.

Main Results:

• Bacterial adhesion extent correlated well with thermodynamic predictions.
• Adhesion was greater on hydrophilic surfaces when bacterial surface tension exceeded the medium's surface tension, and vice versa.
• The study successfully determined bacterial surface tensions, which agreed with other established methods.

Conclusions:

• Thermodynamic principles accurately predict bacterial adhesion to polymeric surfaces.
• The adhesion assay provides a reliable method for quantifying bacterial surface tension.
• Understanding surface tension interactions is key to controlling bacterial adhesion in various applications.