Fluorescence and other types of photoluminescence spectroscopy and imaging are highly advantageous as analytical techniques. These techniques are very sensitive, rapid, non-invasive, and capable of multiplexed detection. Photophysical processes such as Förster resonance energy transfer (FRET) or photoinduced electron transfer can modulate luminescence “on” or “off,” and provide exciting opportunities for developing analytical probes for the detection of a wide range of chemical and biological targets.
Luminescent nanoparticles provide additional opportunities to capitalize on the advantages of fluorescence. These materials will often have superior brightness and photostability than molecular luminophores, and provide surface area that can used as scaffold for building multifunctional, biomolecular architectures and/or carrying therapeutics.
We are interested in developing new analytical applications for luminescent nanoparticles and other luminophores, with a special emphasis on bio/chemical sensing, imaging, and assays.
Biomarkers are molecules that, by virtue of their concentration or activity, are indicative of certain disease states, pathogens, normal biological processes, or even therapeutic efficacy. Improved methods for the sensitive and specific detection of biomarkers are critically needed for clinical diagnostics and biomedical research.
We are using luminescent materials, in combination with spectroscopy, imaging, FRET, bioconjugate chemistry, and surface chemistry to develop new strategies and devices for bio/chemical sensing and bioassays. We aim to detect target proteins, enzyme activity, nucleic acids, and other biomolecules, both in vitro and in cellular contexts.
Research Project Areas
Materials synthesis and biofunctionalization. Materials science continues to develop new and interesting luminescent materials that may be advantageous for our research. We synthesize and/or chemically modify these materials for applications in bioanalysis and bioimaging. Semiconductor quantum dots are one of the most interesting and advantageous materials we use in our research; however, we are also interested in lanthanide complexes, fluorescent polymer materials, and magnetic materials.
Understanding the nanoparticle interface. Nanoparticles are heterogeneous systems that can be homogeneously dispersed, support polyvalent modification with biomolecular probes, and have tailorable surface properties (e.g., charge, polarity). We are learning how to rationally design nanoparticle-bioconjugates for optimum performance in biosensing and bioassays. The nanoparticle interface, and its interactions with both the biological target and background materials, can potentially affect its sensitivity, selectivity, stability, and many other properties. An understanding of these interactions and their implications will allow surface chemistry to be tuned and exploited to maximize analytical performance.
New energy transfer configurations for sensing and imaging. The ability to turn luminescent materials, such as QDs, “ON” and “OFF” via energy transfer processes is essential to the development of biosensors and imaging probes. We are developing methods of assembling multiple energy transfer pathways around a nanoparticle to “program” it with multiple functions, e.g., the orthogonal detection of multiple biomarkers. We also interested in adapting energy transfer configurations for use with low-cost, portable diagnostic devices. Lanthanide-based system are also being developed and combine spectral, intensity-based, and temporal modulation to create novel bioprobes and molecular logical operators.
Point-of-care diagnostic devices. A huge fraction of the healthcare costs in northern and rural Canadian communities is associated with transportation of patients to urban centres for diagnostics and treatment. We are aiming to exploit nanotechnology and luminescent materials to develop new diagnostic devices that can be used on-site in a doctor’s office or hospital room. Such devices would also reduce healthcare costs and increase efficiency in urban centers, help enable enable personalized medicine, and would potentially valuable for the Developing World, field deployment, and other low-resource settings. Some of the guiding principles of this research are the need for low-cost, low-power, portability, integration with mass-produced consumer electronic devices (e.g., smartphones).
Intracellular sensing. Cells are perhaps the most complex ‘beakers’ known, with an immense number of chemical reactions occurring in concert in a very small volume. A detailed understanding of cellular processes and their dynamic responses to stimuli will provide new insights into health and disease, including new and improved methods for diagnosis and therapy. We are developing FRET-based probes and imaging methods that can be used to quantitatively track enzyme activity and cascades in cells, the expression of genes and other nucleic acid targets (e.g., miRNA), and other intracellular or extracellular processes.