AgNC’s as Acceptor/donor Pairs in FRET-based Excitonic Waveguides

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Student Presentation

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Faculty Sponsor

Bill Knowlton


Silver nanoclusters (AgNCs) contain ~20 atoms and exhibit discrete electronic transition states that are not present in the bulk. When synthesized onto synthetic DNA strands, they also have chromophore-like behavior with detectable absorption and emission spectra. Methods for producing stable DNA/AgNC complexes have been reported with tunable spectra based on their particle size and hybridization domains. Presently, most studies have focused on the use of AgNCs as molecular beacons, rulers, and detectors. To date, little work has been done to demonstrate their viability in excitonic Förster resonant energy transfer (FRET) systems – thereby replacing traditional chromophores as acceptor/donor pairs. Here, we report the use of AgNCs as both an acceptor and a donor in an excitonic waveguide.

In our design, FAM was the primary donor chromophore, two AgNCs provided intermediate acceptor/donor configurations, and Cy5 was the terminal acceptor chromophore. Emission spectroscopy was used to examine FRET of the FAM (F) to two AgNCs (SS) to Cy5 (C) resulting in an FSSC waveguide configuration. Fluorescent emission and hybridization kinetics data both showed increased emission at 668 nm immediately following AgNC addition thereby demonstrating an FSSC waveguide. Further investigation of AgNCs may lead to greater exciton transfer across these types of systems.

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