Viability of near-infrared fluorescence of single-walled carbon nanotubes for detection of DNA sequences

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Esther S Jeng, ejeng@uiuc.edu, Department of Chemical and Biomolecular Engineering / Strano Research Group, University of Illinois Urbana-Champaign, 600 S. Mathews Ave., Urbana, IL 61801 and Michael S. Strano, strano@uiuc.edu, Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801.
Individually dispersed semiconducting single-walled carbon nanotubes (SWNT) fluoresce across their band-gap at near-infrared (nIR) wavelengths. In the nIR region cell autofluorescence as well as tissue and blood absorption is low. For these reasons, SWNT have the potential to be utilized as biological sensors. SWNT fluorescence is sensitive to surface events, as the fluorescence energy of a tube can change with surface coverage. We are able to non-covalently adsorb oligonucleotide strands to the surface of SWNT, resulting in a colloidally stable solution. The addition of the complementary strand to the oligo-SWNT solution results in a fluorescence energy modulation allowing for detection of specific DNA sequences. We investigate the use and viability for using this system as a DNA sensor.