A route to brightly fluorescent carbon nanotubes for near-infrared imaging in mice

Nat Nanotechnol. 2009 Nov;4(11):773-80. doi: 10.1038/nnano.2009.294. Epub 2009 Oct 11.


The near-infrared photoluminescence intrinsic to semiconducting single-walled carbon nanotubes is ideal for biological imaging owing to the low autofluorescence and deep tissue penetration in the near-infrared region beyond 1 microm. However, biocompatible single-walled carbon nanotubes with high quantum yield have been elusive. Here, we show that sonicating single-walled carbon nanotubes with sodium cholate, followed by surfactant exchange to form phospholipid-polyethylene glycol coated nanotubes, produces in vivo imaging agents that are both bright and biocompatible. The exchange procedure is better than directly sonicating the tubes with the phospholipid-polyethylene glycol, because it results in less damage to the nanotubes and improves the quantum yield. We show whole-animal in vivo imaging using an InGaAs camera in the 1-1.7 microm spectral range by detecting the intrinsic near-infrared photoluminescence of the 'exchange' single-walled carbon nanotubes at a low dose (17 mg l(-1) injected dose). The deep tissue penetration and low autofluorescence background allowed high-resolution intravital microscopy imaging of tumour vessels beneath thick skin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Vessels / pathology
  • Cell Line, Tumor
  • Fluorescence
  • Humans
  • Imaging, Three-Dimensional / methods*
  • Luminescent Measurements
  • Mice
  • Microscopy, Atomic Force
  • Molecular Imaging / methods*
  • Nanotubes, Carbon / chemistry*
  • Spectroscopy, Near-Infrared*
  • Spectrum Analysis, Raman


  • Nanotubes, Carbon