| Single-Walled Carbon Nanotube Detection of Ion-Mediated DNA Polymorphism | ||
| Daniel A. Heller1, Esther S. Jeng2, Tsun-Kwan Yeung3, Brittany M. Martinez2, Anthonie E. Moll2, Joseph B. Gastala4 and Michael S. Strano5, (1)Department of Chemistry, University of Illinois at Urbana-Champaign, 104 RAL, MC-712, 600 S. Mathews Ave., Urbana, IL 61801, (2)Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 104 RAL, MC-712, 600 S. Mathews Ave., Urbana, IL 61801, (3)Department of Physics, University of Illinois at Urbana-Champaign, 104 RAL, MC-712, 600 S. Mathews Ave., Urbana, IL 61801, (4)Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana-Champaign, 600 S. Mathews, Urbana, IL 61821, (5)Chemical and Biomolecular Engineering, University of Illinois, Urbana-Champaign, 600 S. Mathews, Urbana, IL 61821 The transition of DNA secondary structure from the B to Z conformation was detected via modulation of the intrinsic near-infrared fluorescence of single-walled carbon nanotubes. A reversible shift in emission energy of DNA-encapsulated nanotubes was found to closely match the thermodynamics of the transition of unbound DNA. A 30-mer oligonucleotide on the nanotube surface behaves as if it were shortened by 1/6 due to the propagation length of the B-Z transition. The system motivates new near-infrared biosensors capable of operation in strongly scattering or absorbing media, and we demonstrate the optical detection of the B-Z transition from localized complexes within live mammalian cells.
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