Optical detection of DNA conformational polymorphism on single-walled carbon nanotubes

Research areas:
  • Uncategorized
Year: 2006
Type of Publication: Article
  • D. A. Heller, T. K. Yeung E. S. Jeng
Journal: Science Volume: 311
Number: 5760 Pages: 508-511
Month: JAN 27 2006
PT: J; TC: 226; UT: WOS:000235071400042
The transition of DNA secondary structure from an analogous B to Z conformation modulates the dielectric environment of the single-waited carbon nanotube (SWNT) around which it is adsorbed. The SWNT band-gap fluorescence undergoes a red shift when an encapsulating 30-nucleotide oligomer is exposed to counter ions that screen the charged backbone. The transition is thermodynamically identical for DNA on and off the nanotube, except that the propagation length of the former is shorter by five-sixths. The magnitude of the energy shift is described by using an effective medium model and the DNA geometry on the nanotube sidewall. We demonstrate the detection of the B-Z change in whole blood, tissue, and from within living mammalian cells.