(127c) Single-Walled Carbon Nanotube Labels and Optical Sensors in Live Cells Conference: AIChE Annual MeetingYear: 2005Proceeding: 2005 AIChE Annual MeetingGroup: Biomedical Applications of Nanotechnology (Bionanotechnology)Session: Nanomaterials for in vivo and in vitro Imaging and Chemical Sensing Time: Monday, October 31, 2005 - 3:55pm-4:15pm Authors: Heller, D. A., Massachusetts Institute of Technology Baik, S., Sungkyunkwan University Moll, A. E., University of Illinois at Urbana-Champaign Yeung, T., University of Illinois at Urbana-Champaign Eurell, T. E., University of Illinois at Urbana-Champaign Strano, M. S., Massachusetts Institute of Technology Martinez, B. M., University of Illinois at Urbana-Champaign Jeng, E. S., University of Illinois at Urbana-Champaign Complexes of DNA and single-walled carbon nanotubes (SWNT) exhibit long-lived, modifiable near-infrared fluorescence emission which was used to fabricate long-term labels and optical sensors within cells and tissues. Nanotube fluorescence is in the near-infrared region and does not photobleach under prolonged excitation, permitting continuous monitoring through biological media for experiments lasting several hours. The transition of the DNA secondary structure from the B to Z conformation was detected via modulation of the intrinsic near-infrared fluorescence of SWNT. A reversible shift in emission energy of DNA-encapsulated nanotubes was found to closely match the thermodynamics of the transition of unbound DNA. DNA-nanotube complexes were taken into endosomes, situated near the cell nucleus, and remained visible after multiple cell divisions. The sensors demonstrated optical detection of the DNA B-Z transition within mammalian cells, muscle tissue and whole blood.