Bacterial adhesion onto materials with specific surface chemistries under flow conditions

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Microbiology

Background:

• Bacterial adhesion to biomaterials is a critical factor in device-associated infections.
• Understanding surface chemistry's role in bacterial adhesion is crucial for developing infection-resistant materials.

Purpose of the Study:

• To investigate Staphylococcus epidermidis adhesion on surfaces with varying terminal chemical functionalities under flow conditions.
• To correlate bacterial adhesion with surface properties like free energy and shear rate.

Main Methods:

• Fabrication of glass surfaces with self-assembled alkyl silane monolayers (methyl, amino, carboxyl terminated).
• Surface characterization using contact angle, atomic force microscopy, and X-ray photoelectron spectroscopy.
• Evaluation of bacterial adhesion in a parallel plate flow chamber at different shear rates.

Main Results:

• Bacterial adhesion varied significantly with surface functionality: CH(3) > NH(2) (positive) > NH(2) (neutral) > COOH > OH.
• Increased surface free energy reduced adhesion for a hydrophilic bacterial strain, aligning with thermodynamic theory.
• Higher shear rates complicated adhesion predictability, revealing macromolecular interactions on NH(2)- and COOH-terminated surfaces.

Conclusions:

• Surface terminal functionality is a key determinant of Staphylococcus epidermidis adhesion.
• Thermodynamic principles govern adhesion, but shear rate and macromolecular interactions play significant roles.
• Tailoring surface chemistry is essential for controlling bacterial adhesion on biomaterials.