The research activities of Dr. Denis Boudreauat Université Laval and the Center for Optics, Photonics and Lasers (COPL) in Québec lie at the interface between optical sensor design, molecular electronic/vibrational spectroscopy, and luminescent and plasmonic nanomaterial synthesis for industrial, biological and environmental sensing applications.

Boudreau’s graduate students use Raman and surface-enhanced Raman spectroscopy, time-resolved, and steady-state fluorescence and plasmon-enhanced fluorescence spectrometry, and darkfield/epifluorescence imaging on a daily basis.

Biological Sensing

The team’s FERGIE-facilitated research projects involve (1) surface-enhanced Raman spectrometry of metabolic biomarkers, (2) synthesis and characterization of plasmonic nanoparticles for biosensor design, and (3) optical waveguide-based optical probes for in vivo and in vitro biological sensing.

FERGIE in Action (Project 1)

Synthesis and Characterization of Plasmonic Nanoparticles for Biosensor Design

The research team of Dr. Boudreau deals in the synthesis of luminescent nanoparticles. These particles contain a plasmonic core coated with fluorophore-doped concentric dielectric layers. Fluorophores are generally sensitive to various chemical and physical stimuli.

Since the core’s size and shape have a significant influence on luminescent behavior, the team used single-particle spectroscopy to ascertain design rules that will result in nanostructures with improved properties.

Electron Microscopy

In concert with a customized confocal microscope, FERGIE is used for collecting single-particle fluorescence and scattering data, which is subsequently correlated with electron microscopy data. The ease with which FERGIE can be coupled to an optical setup, either free-space or via an optical fiber, makes this very easy.

Optical Waveguide-Based Optical Probes for In Vitro and In Vivo Biological Sensing

To image the evolution of key cell metabolites, species-selective nanoparticles are connected to microscope slides and allowed to come into contact with cell cultures. Likewise, to perform remote biological or chemical sensing, the same plasmonic nanomaterials are being grafted on the tip of customized optical fibers.

Resolution

Present applications include in vivo molecular sensing in model animals and process monitoring in water treatment plants. In time, this fiber sensor will integrate multichannel architectures and fluorescent sensing structures responsive to various microbial metabolites, making it a flexible tool for sensing the intestinal microbiome with unprecedented resolution.

Surface-Enhanced Raman Spectrometry of Metabolic Biomarkers

Dr. Boudreau’s team is working with other research teams on the development of methodologies based on surface-enhanced Raman spectrometry (SERS) and plasmonic nanomaterials for in situ detection and quantification of cell metabolic markers.

Target applications include analyzing the acclimation of phytoplankton to variations in global climate and also in vivo biomonitoring of cholic acid derivatives in the gut microbiota.