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Proceedings Paper

Photo-switchable quantum dots based on reversible FRET
Author(s): Qirui Fan; Gauri Nabar; Carl Miller; Carlos Castro; Jessica Winter
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Paper Abstract

Super-resolution fluorescence microscopy is anticipated to be a powerful tool in observing biological structures and processes smaller than the diffraction limit of light microscopy (~200nm). Yet, many super-resolution techniques (STORM/PALM, STED) employ photo-switchable fluorescent probes (i.e., dyes and fluorescent proteins) that are limited in brightness and stability, reducing potential image resolution. Here, we describe photo-switchable quantum dots (QDs) with enhanced brightness and stability, and excellent optical properties, including narrow emission spectra and broad excitation spectra, compared to fluorescent dyes. These QDs are composed of one green QD, one gold nanoparticle (AuNP), and complimentary single stranded DNA (ssDNA) modified with photo-sensitive azobenzene groups bound to each of the particles. Because of the azobenzene photosensitive property, the ssDNA strands hybridize when excited with visible light, yielding a QD-AuNP conjugate in which QD fluorescence is quenched through Förster resonance energy transfer (FRET); and dehybridize under visible light, yielding separate QDs and AuNPs that are free to diffuse from each other. Because FRET is strongly distance dependent (i.e., α 1/r6, in this case, a few nanometers), QD fluorescence is restored. Moreover, the photo-switchable QD-AuNP conjugate scheme has the potential to be integrated with a DNA nano-machine platform, adding the potential for photo-manipulated functionality. As a preliminary proof of concept, we tethered different nanocomponents, including QD micelle assemblies and AuNPs, to DNA origami structures (hinge and platform shapes) using ssDNA hybridization.

Paper Details

Date Published: 20 February 2014
PDF: 8 pages
Proc. SPIE 8954, Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XI, 89540D (20 February 2014); doi: 10.1117/12.2038611
Show Author Affiliations
Qirui Fan, The Ohio State Univ. (United States)
Gauri Nabar, The Ohio State Univ. (United States)
Carl Miller, The Ohio State Univ. (United States)
Carlos Castro, The Ohio State Univ. (United States)
Jessica Winter, The Ohio State Univ. (United States)

Published in SPIE Proceedings Vol. 8954:
Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XI
Alexander N. Cartwright; Dan V. Nicolau, Editor(s)

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