(291o) Single-Walled Carbon Nanotube Detection of Ion-Mediated DNA Polymorphism Conference: AIChE Annual MeetingYear: 2005Proceeding: 2005 AIChE Annual MeetingGroup: 5th Topical Conference on Nanoscale Science and EngineeringSession: Poster Session: Nanoscale Science and Engineering Time: Tuesday, November 1, 2005 - 6:00pm-8:30pm Authors: Heller, D. A., Massachusetts Institute of Technology Strano, M. S., Massachusetts Institute of Technology Jeng, E. S., University of Illinois at Urbana-Champaign Yeung, T., University of Illinois at Urbana-Champaign Martinez, B. M., University of Illinois at Urbana-Champaign Moll, A. E., University of Illinois at Urbana-Champaign Gastala, J. B., University of Illinois, Urbana-Champaign 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.