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Labeling TiO 2 Nanoparticles with Dyes for Optical Fluorescence Microscopy and Determination of TiO 2 –DNA Nanoconjugate Stability
Author(s) -
Thurn Kenneth T.,
Paunesku Tatjana,
Wu Aiguo,
Brown Eric M. B.,
Lai Barry,
Vogt Stefan,
Maser Jörg,
Aslam Mohammed,
Dravid Vinayak,
Bergan Raymond,
Woloschak Gayle E.
Publication year - 2009
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200801458
Subject(s) - fluorescence , fluorescence microscope , nanoparticle , intracellular , biophysics , confocal microscopy , oligonucleotide , microscopy , förster resonance energy transfer , dna , materials science , nanotechnology , fluorescence lifetime imaging microscopy , population , chemistry , biochemistry , microbiology and biotechnology , biology , physics , quantum mechanics , optics , demography , sociology
Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO 2 ) nanoparticles. These nanoparticles, when electronically linked to single‐stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO 2 –DNA nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO 2 nanoparticles and TiO 2 –DNA nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO 2 nanoparticle uptake in a large population of living cells (>10 4 cells). X‐ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO 2 –DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO 2 –DNA nanoconjugates in malignant cells.