Surface potential measurement of bacteria using Kelvin probe force microscopy

Area of Science:

• Microbiology
• Surface Science
• Nanotechnology

Background:

• Microbial adhesion to surfaces is crucial in many settings, including medicine.
• Surface potential, a key physical characteristic, significantly influences this adhesion process.
• Kelvin probe force microscopy (KPFM) is an atomic force microscopy (AFM) technique for nanoscale surface potential measurement.

Purpose of the Study:

• To investigate the role of surface potential in microbial adhesion to medically relevant substrates.
• To demonstrate the application of KPFM for characterizing microbial surface potential.
• To analyze differences in surface potential of bacterial cells on stainless steel and gold.

Main Methods:

• Utilized Kelvin probe force microscopy (KPFM) combined with atomic force microscopy (AFM).
• Generated simultaneous surface potential and topographical maps of bacterial cells.
• Characterized individual methicillin-resistant Staphylococcus aureus USA100 cells on stainless steel and gold surfaces.

Main Results:

• Observed distinct differences in the surface potential of microbial membranes on stainless steel and gold.
• Quantified the surface potential difference at the interface between microbial cells and substrates.
• Established a procedure for KPFM analysis of microbial surface potential.

Conclusions:

• KPFM is a powerful tool for studying microbial adhesion by mapping nanoscale surface potential.
• Changes in microbial membrane surface potential upon adhesion can be detected and analyzed.
• This approach provides insights into the physical basis of microbial-surface interactions.