A route to brightly fluorescent carbon nanotubes for near-infrared imaging in mice.
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.
Welsher
Kevin
K
Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
Liu
Zhuang
Z
Sherlock
Sarah P
SP
Robinson
Joshua Tucker
JT
Chen
Zhuo
Z
Daranciang
Dan
D
Dai
Hongjie
H
D000818:Animals; D001808:Blood Vessels / Q000473:pathology; D045744:Cell Line, Tumor; D005453:Fluorescence; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008163:Luminescent Measurements; D051379:Mice; D018625:Microscopy, Atomic Force; D057054:Molecular Imaging / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared; D013059:Spectrum Analysis, Raman
D037742:Nanotubes, Carbon