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DNA “Nanolamps”: “Clicked” DNA Conjugates with Photon Upconverting Nanoparticles as Highly Emissive Biomaterial

Authors

  • Dipl. Ing. Moritz M. Rubner,

    1. Institute for Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-44825
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  • Dipl.-Chem. Daniela E. Achatz,

    1. Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg (Germany), 93040 Regensburg
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  • Dr. Heike S. Mader,

    1. Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg (Germany), 93040 Regensburg
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  • Dr. Judith A. Stolwijk,

    1. Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg (Germany), 93040 Regensburg
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  • Prof. Dr. Joachim Wegener,

    1. Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg (Germany), 93040 Regensburg
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  • Prof. Gregory S. Harms,

    1. Bio-Imaging Center and Rudolf Virchow Center, University of Würzburg (Germany), Josef-Schneider-Strasse 2, 97080 Würzburg (Germany)
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  • Prof. Dr. Otto S. Wolfbeis,

    Corresponding author
    1. Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg (Germany), 93040 Regensburg
    • Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg (Germany), 93040 Regensburg
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  • Prof. Dr. Hans-Achim Wagenknecht

    Corresponding author
    1. Institute for Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-44825
    • Institute for Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-44825
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Abstract

Upconverting nanoparticles (UCNPs) are a highly attractive tool owing to their unique property of showing visible luminescence when excited in the near-infrared (NIR) region. Plain UCNPs have no biorecognition capabilities, but functionalization of their surface with azido groups renders them conjugatable to ethynyl-modified oligonucleotides in a bioorthogonal fashion. Single-stranded DNA was covalently attached to the surface of UCNPs by click chemistry and purified by size exclusion chromatography (SEC) at elevated temperature. Covalent attachment was evidenced by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. DNA conjugation makes the particle soluble in water and enables it to recognize its counter strand. Such UCNPs are capable of nonspecifically crossing cell membranes. Confocal microscopy reveals the high potential of the bright UCNPs for live cell imaging in the NIR, where the UCNP–DNA conjugates can be considered to act as a kind of nano-sized lamp. Furthermore, cross-linking of those DNA nanolamps yields highly emissive aggregates.

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