Resolving physical interactions between bacteria and nanotopographies with focused ion beam scanning electron...

Area of Science:

• Biomaterials Science
• Microbiology
• Nanotechnology

Background:

• Understanding bacteria-nanotopography interactions is crucial for developing effective antibacterial strategies.
• Previous studies often lacked detailed analysis of the physical interface between bacteria and nanostructured surfaces.

Purpose of the Study:

• To quantitatively analyze the three-dimensional interface between bacteria (Staphylococcus aureus, Escherichia coli) and nanotopographies.
• To establish a framework for determining antibacterial mechanisms based on physical interactions at the nanoscale.

Main Methods:

• Utilized focused ion beam milling and scanning electron microscopy for 3D reconstruction of bacteria-nanotopography interfaces.
• Performed 3D morphometric analysis to quantify contact area and bacterial envelope changes.
• Investigated various nanotopography densities and tip diameters.

Main Results:

• Nanotopographies with 36-58 structures/µm² and 27-50 nm tips caused envelope deformation and penetration.
• Higher densities (137 structures/µm²) led to envelope penetration, mechanical rupture, and cytosolic leakage.
• Low densities (8 structures/µm²) with large tips (>100 nm) resulted in bacterial adhesion between structures and cell impedance.

Conclusions:

• Nanotopography characteristics significantly dictate antibacterial effects through physical interactions.
• 3D morphometric analysis provides an objective method to elucidate nanotopography-mediated antibacterial mechanisms.
• Tailoring nanotopography design can control bacterial responses, from deformation to rupture and impedance.