Multimodal optical sensing and analyte specificity using single-walled carbon nanotubes

Nat Nanotechnol. 2009 Feb;4(2):114-20. doi: 10.1038/nnano.2008.369. Epub 2008 Dec 14.


Nanoscale sensing elements offer promise for single-molecule analyte detection in physically or biologically constrained environments. Single-walled carbon nanotubes have several advantages when used as optical sensors, such as photostable near-infrared emission for prolonged detection through biological media and single-molecule sensitivity. Molecular adsorption can be transduced into an optical signal by perturbing the electronic structure of the nanotubes. Here, we show that a pair of single-walled nanotubes provides at least four modes that can be modulated to uniquely fingerprint agents by the degree to which they alter either the emission band intensity or wavelength. We validate this identification method in vitro by demonstrating the detection of six genotoxic analytes, including chemotherapeutic drugs and reactive oxygen species, which are spectroscopically differentiated into four distinct classes, and also demonstrate single-molecule sensitivity in detecting hydrogen peroxide. Finally, we detect and identify these analytes in real time within live 3T3 cells, demonstrating multiplexed optical detection from a nanoscale biosensor and the first label-free tool to optically discriminate between genotoxins.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Alkylating Agents / pharmacology
  • Animals
  • Biosensing Techniques / instrumentation
  • Biosensing Techniques / methods*
  • Cells / drug effects*
  • Cytotoxins / pharmacology
  • DNA Damage / drug effects
  • DNA, Single-Stranded / drug effects
  • Infrared Rays
  • Luminescence
  • Luminescent Agents / analysis
  • Luminescent Agents / radiation effects
  • Luminescent Measurements / instrumentation
  • Luminescent Measurements / methods*
  • Mice
  • Nanotechnology / methods
  • Nanotubes, Carbon / chemistry*
  • Reactive Oxygen Species / pharmacology
  • Sensitivity and Specificity
  • Spectrophotometry, Infrared / instrumentation
  • Spectrophotometry, Infrared / methods
  • Static Electricity


  • Alkylating Agents
  • Cytotoxins
  • DNA, Single-Stranded
  • Luminescent Agents
  • Nanotubes, Carbon
  • Reactive Oxygen Species