Near-infrared optical sensors based on single-walled carbon nanotubes

Nat Mater. 2005 Jan;4(1):86-92. doi: 10.1038/nmat1276. Epub 2004 Dec 12.


Molecular detection using near-infrared light between 0.9 and 1.3 eV has important biomedical applications because of greater tissue penetration and reduced auto-fluorescent background in thick tissue or whole-blood media. Carbon nanotubes have a tunable near-infrared emission that responds to changes in the local dielectric function but remains stable to permanent photobleaching. In this work, we report the synthesis and successful testing of solution-phase, near-infrared sensors, with beta-D-glucose sensing as a model system, using single-walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules. New types of non-covalent functionalization using electron-withdrawing molecules are shown to provide sites for transferring electrons in and out of the nanotube. We also show two distinct mechanisms of signal transduction-fluorescence quenching and charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.

Publication types

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

MeSH terms

  • Biosensing Techniques*
  • Fluorescence*
  • Glucose / analysis*
  • Nanotechnology / methods*
  • Nanotubes, Carbon / chemistry*
  • Optics and Photonics


  • Nanotubes, Carbon
  • Glucose