Raman microscopy of bacteria

Bacteria give distinctive Raman spectra that in many cases reveal what species, or sub-species (strain) they are.

The main focus of this project is to use these distinct Raman features to identify and distinguish between two species of oral bacteria. Using a confocal Raman microscope system, we attempt to map biofilms of the bacteria by species, and use the maps to get a relative concentration estimate. Determining the relative concentrations of these two species may be an indicator of a patient’s oral health, as an abundance of S. mutans has been linked to higher risk of tooth decay. This work is performed in collaboration with Professor Rob Quivey and the Center for Oral Biology.

The biofilms studied in this project are currently grown on glass slides. For some experiments, it may be desirable to look at the biofilms in situ. Unfortunately, glass is a substrate that is typically avoided in biomedical Raman spectroscopy, due to its high fluorescence. Commonly used low-order polynomial background removal techniques fail to consistently remove artifacts from the glass spectral contaminant. We have developed a method to include reference spectra from known spectral contaminants (like glass) in background removal techniques. This work has been published in The Analyst. MATLAB code for this algorithm can be found in our Downloads page.

(Note: this project is currently in hibernation.)