Intracellular in situ labeling of TiO2 nanoparticles for fluorescence microscopy detection

Koshonna Brown, Ted Thurn, Lun Xin, William Liu, Remon Bazak, Si Chen, Barry Lai, Stefan Vogt, Chris Jacobsen, Tatjana Paunesku, Gayle E. Woloschak*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Titanium dioxide (TiO2) nanoparticles are produced for many different purposes, including development of therapeutic and diagnostic nanoparticles for cancer detection and treatment, drug delivery, induction of DNA double-strand breaks, and imaging of specific cells and subcellular structures. Currently, the use of optical microscopy, an imaging technique most accessible to biology and medical pathology, to detect TiO2 nanoparticles in cells and tissues ex vivo is limited with low detection limits, while more sensitive imaging methods (transmission electron microscopy, X-ray fluorescence microscopy, etc.) have low throughput and technical and operational complications. Herein, we describe two in situ posttreatment labeling approaches to stain TiO2 nanoparticles taken up by the cells. The first approach utilizes fluorescent biotin and fluorescent streptavidin to label the nanoparticles before and after cellular uptake; the second approach is based on the copper-catalyzed azide-alkyne cycloaddition, the so-called Click chemistry, for labeling and detection of azide-conjugated TiO2 nanoparticles with alkyneconjugated fluorescent dyes such as Alexa Fluor 488. To confirm that optical fluorescence signals of these nanoparticles match the distribution of the Ti element, we used synchrotron X-ray fluorescence microscopy (XFM) at the Advanced Photon Source at Argonne National Laboratory. Titanium-specific XFM showed excellent overlap with the location of optical fluorescence detected by confocal microscopy. Therefore, future experiments with TiO2 nanoparticles may safely rely on confocal microscopy after in situ nanoparticle labeling using approaches described here.

Original languageEnglish (US)
Pages (from-to)464-476
Number of pages13
JournalNano Research
Issue number1
StatePublished - Jan 1 2018


  • Click reaction
  • TiO nanoparticles
  • anatase
  • biotin–streptavidin
  • fluorescence microscopy
  • synchrotron X-ray

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Intracellular in situ labeling of TiO2 nanoparticles for fluorescence microscopy detection'. Together they form a unique fingerprint.

Cite this