Nano Archive

Detection of DNA hybridization using the near-infrared band-gap fluorescence of single-walled carbon nanotubes

Jeng, E. S. and Moll, A. E. and Roy, A. C. and Gastala, J. B. and Strano, M. S. (2006) Detection of DNA hybridization using the near-infrared band-gap fluorescence of single-walled carbon nanotubes. NANO LETTERS, 6 (3). pp. 371-375. ISSN 1530-6984

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We demonstrate the optical detection of DNA hybridization on the surface of solution suspended single-walled carbon nanotubes (SWNTs) through a SWNT band gap fluorescence modulation. Hybridization of a 24-mer oligonucleotide sequence with its complement produces a hypsochromic shift of 2 meV, with a detection sensitivity of 6 nM. The energy shift is modeled by correlating the surface coverage of DNA on SWNT to the exciton binding energy, yielding an estimated initial fractional coverage of 0.25 and a final coverage of 0.5. Hybridization on the nanotube surface is confirmed using Forster resonance energy transfer of fluorophore-labeled DNA oligonucleotides. This detection is enabled through a new technique to suspend SWNTs using adsorption of single-stranded DNA and subsequent removal of free DNA from solution. While the kinetics of free DNA hybridization are relatively fast (< 10 min), the kinetics of the process on SWNTs are slower under comparable conditions, reaching steady state after 13 h at 25 degrees C. A second-order kinetic model yields a rate constant of k = 4.33 x 10(5) (M h)(-1). This optical, selective detection of specific DNA sequences may have applications in the life sciences and medicine as in vitro or in vivo detectors of oligonucleotides.

Item Type:Article
Uncontrolled Keywords:Singlewalled nanotube ; Kinetic model ; Second order ; Steady state ; Adsorption ; Energy transfer ; Resonance energy ; Binding energy ; Electronic properties ; Energy gap ; Near infrared radiation ; Hybridization ; DNA ;
Subjects:Biomedical Science > Nanoscale biological processes
ID Code:2760
Deposited By:Lesley Tobin
Deposited On:14 Jan 2009 16:13
Last Modified:02 Mar 2009 14:39

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