Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping

Nat Biotechnol. 2004 Jan;22(1):93-7. doi: 10.1038/nbt920. Epub 2003 Dec 7.


The use of near-infrared or infrared photons is a promising approach for biomedical imaging in living tissue. This technology often requires exogenous contrast agents with combinations of hydrodynamic diameter, absorption, quantum yield and stability that are not possible with conventional organic fluorophores. Here we show that the fluorescence emission of type II quantum dots can be tuned into the near infrared while preserving absorption cross-section, and that a polydentate phosphine coating renders them soluble, disperse and stable in serum. We then demonstrate that these quantum dots allow a major cancer surgery, sentinel lymph node mapping, to be performed in large animals under complete image guidance. Injection of only 400 pmol of near-infrared quantum dots permits sentinel lymph nodes 1 cm deep to be imaged easily in real time using excitation fluence rates of only 5 mW/cm(2). Taken together, the chemical, optical and in vivo data presented in this study demonstrate the potential of near-infrared quantum dots for biomedical imaging.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Fluorescent Dyes
  • Image Processing, Computer-Assisted
  • Lymph Nodes / pathology
  • Lymphatic Metastasis
  • Mice
  • Microscopy, Fluorescence / methods*
  • Neoplasms / surgery*
  • Phosphines / chemistry
  • Sentinel Lymph Node Biopsy / methods*
  • Spectroscopy, Near-Infrared
  • Swine
  • Time Factors


  • Fluorescent Dyes
  • Phosphines
  • phosphine