Category: High-Definition Biotechnology

1240-A - Optical Nanosensors for Monitoring 3D Oxygen Gradients in P. aeruginosa Biofilms

Monday, February 5, 2018
2:00 PM - 3:00 PM

Bacterial biofilms are the cause of chronic infections of wounds, medical implants, and immunocompromised patients such as those with cystic fibrosis. These biofilms often exhibit antibiotic resistance that makes them medically difficult to treat. Being able to monitor target analytes within the structure of the biofilm is critical for understanding biofilm disease biology and its response to treatment. Oxygen consumption can be used as a measure of metabolic activity in facultative aerobes, but current methods such as microelectrodes limit monitoring to one dimension and cannot adequately capture dynamics. However, biofilms are complex three dimensional structures that require higher resolution approaches to gain a more complete understanding of activity. Traditional measurements require physically moving the microelectrode, which is inherently disruptive to biofilm structure and obscures rapid dynamics within the system, which can potentially alter results. Here, we demonstrate optical oxygen-sensitive nanosensors that were used to measure 3D oxygen gradients and growth oscillations in Pseudomonas aeruginosa biofilms with minimal disruption to the biofilm structure. Using this approach, we improved on traditional electrode-based 1D methods of measuring oxygen profiles by investigating both the spatial and temporal variation in oxygen concentration during biofilm growth and under antibiotic attack. We observed spatial gradients in oxygen concentration during biofilm growth, attributed to nutrient consumption at the edges of the biofilm. We also studied 3D oxygen gradients during antibiotic attack and found that oxygen was present at greater depths compared to untreated controls, consistent with cell death or a transition to anaerobic respiration. This new approach to biological interrogation provides higher resolution data, with improved temporal resolution, while minimizing the impact of the measurement on the biofilm itself.

Megan P. Jewell

Graduate Research Assistant
Colorado School of Mines
Golden, CO

Megan is a third year PhD candidate at Colorado School of Mines in Golden, CO. She received her B.S. in Chemical Engineering from West Virginia University, Morgantown, WV. Her research focuses on designing optical nanosensors to study 3D metabolite gradients in bacterial biofilms.