UBC Theses and Dissertations
A long-wavelength quantum dot-concentric Förster resonance energy transfer configuration: characterization and application in a multiplexed hybridization assay Li, Jia Jun
Concentric Förster resonance energy transfer (cFRET) based on fluorescent quantum dots as nanoscaffolds is a promising strategy for multiplexed bioanalysis and bioimaging. To expand the scope of prototypical cFRET strategy, which was limited to a particular combination of quantum dot (QD), peptides and fluorescent dyes, work in this thesis adopted a combination of an orange-emitting QD605 and red/deep-red fluorescent dyes Alexa Fluor 633 and Alexa Fluor 680 for the design of a long-wavelength cFRET configuration. This new configuration has shown certain superior properties compared to the prototypical one. Although more susceptible to photobleaching, the long-wavelength cFRET configuration offers much higher signal-to-background ratios in biological samples due to both the excellent brightness of the orange-emitting QD605 and long-wavelength excitation and emission. A rate analysis of both of the competitive and sequential energy transfer pathways revealed the dominant competitive pathway in the long-wavelength cFRET configuration, contrary to a dominant sequential pathway in the prototypical configuration. Moreover, to expand cFRET beyond peptide-linked configurations, an oligonucleotide-linked cFRET configuration was constructed and used to demonstrate the multiplexed detection of unlabeled target oligonucleotides through efficient toehold-mediated strand displacement. Overall, work in this thesis has contributed to evidence of cFRET as a general strategy and expanded it to a wider range of applications.
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