High-resolution three-dimensional imaging of biofilm development using optical coherence tomography

Area of Science:

• Microbiology
• Biomedical Engineering
• Optical Imaging

Background:

• Bacterial biofilms pose significant challenges in healthcare and industry.
• Characterizing biofilm structure in real-time and in situ is crucial for understanding their development and for effective treatment strategies.
• Current imaging techniques may have limitations in penetration depth or require labels.

Purpose of the Study:

• To demonstrate the utility of optical coherence tomography (OCT) for high-resolution, real-time, 3D imaging of Pseudomonas aeruginosa biofilms.
• To investigate the structural development of biofilms within a capillary flow cell model using OCT.
• To compare OCT imaging with established methods like confocal laser scanning microscopy.

Main Methods:

• Utilized optical coherence tomography (OCT) for imaging.
• Employed a standard capillary flow-cell model for Pseudomonas aeruginosa biofilm growth.
• Acquired cross-sectional and volume-rendered 3D OCT images.
• Compared OCT imaging depth and resolution with confocal laser scanning microscopy.

Main Results:

• OCT provided high-resolution, real-time, 3D imaging of biofilm structure and development.
• Complete biofilm development was observed on all flow-cell surfaces due to OCT's penetration depth.
• Biofilm at the bottom exhibited more complex structures (voids, projections, microcolonies) compared to the flatter top biofilm.
• 3D OCT reconstructions were visually comparable to confocal microscopy but achieved greater imaging depths.

Conclusions:

• Optical coherence tomography is a promising non-invasive, label-free imaging modality for biofilm characterization.
• OCT offers real-time, in-situ, and potentially in-vivo imaging capabilities for biofilms.
• The technique allows for detailed analysis of biofilm architecture and development in complex environments.