I. Bioenabled Plasmonic Nanostructures for Sensing and Imaging
We are interested in developing optical sensing systems for studying cellular processes, and for high-throughput screening of drug candidates, proteins and other compounds of security, biomedical and environmental importance. The sensing platforms are based on biofunctionalized plasmonic nanostructures. By incorporating designed biological linkers with surface-anchored plasmonic nanoparticles, we engineer unique optical responses that provide high sensitivity and selectivity for the detection of target even in complex media, and enable facile and low-cost biodiagnostics.
Plasmonic assemblies, constructed with AuNPs functionalized with aptamer or oligonucleotides, were utilized to detect biomolecules such as ATP and microRNA from single cells and in the microenvironment. Disassembly of the nanostructure leads to a decrease in scattering intensity as imaged in dark field microscopy. See ACS Sensors, 2017 and Analyst, 2020.
DNA-AuNP applied as high-mass probe in imaging mass cytometry shows different uptake and retention depending on miR-210 levels. See ACS Appl. Bio. Mater. 2019.
DNA surface density on AuNP matters for toehold mediated strand displacement reaction - implications on designing nucleic acid sensors. See ACS Appl. Nano Mater. 2020.
A new concept of colorimetric sensing of small molecules was achieved by exploring target-controlled permeability change of polyelectrolyte-aptamer (PE-aptamer) multilayer thin film coupled with plasmonic nanoparticles that undergo morphological changes. See JACS, 2013.
II. Hybrid Nanomaterials for Energy Generation and Photochemical Processes
Solar is poised to be a sustainable clean renewable alternative energy. Of the various photovoltaics that convert light to electricity, those based on conjugated polymers and nanoparticles are attractive because of their low cost and ease of fabrication. We are interested in organizing these materials (including metal oxide nanoparticles, semiconductor quantum dots and organic polymers) into hierarchical structures. We aim to increase light absorption through photonic and/or plasmonic enhancements, and to promote charge separation and transport by controlling the interfacial properties. We employ spectroscopies, microscopies, surface analyses and photovoltaic characterizations to elucidate the factors governing device performance. Aside from solar electric conversion, we are also interested in inorganic nanomaterials for photocatalysis, environmental remediation and solar fuel generation.
Mn2+-doped CdS/ZnS quantum dots photocatalyze reductive organic transformations with superior efficiency compared with undoped QDs due to enhanced Auger processes that produce hot electrons. See J. Mater. Chem. A 2022.
Photonic inverse opals of P3HT/TiO2 yield different optical properties and charge generation efficiency, as probed using photoinduced transient absorption spectroscopy. See JPCC, 2017.
Energy alignment at the interface of metal oxide and polymer is governed by trap states and band bending, as studied using ultraviolet photoelectron spectroscopy. Charge transfer from P3HT to TiO2 is significantly enhanced upon passivation. See JPCC, 2018.
Our research is supported by:
- Canada Foundation of Innovation
- Ontario Research Fund
- Natural Science and Engineering Council of Canada
- Petro-Canada
- York University
Our (past and present) collaborators include:
- Professor Peng (Biology)
- Professor Johnson (Chemistry)
- Fluidigm Inc. (now Standard BioTools)
- Professor Kitaev (Wilfrid Laurier University)