title: Liquid crystal phases of DNA: evaluation of DNA organization by two-photon fluorescence microscopy and polarization analysis.
abstract: We report on the investigation of the structure of DNA liquid crystal (LC) phases by means of polarization sensitive two-photon microscopy (PSTPM). DNA was stained with fluorescent dyes, an intercalator propidium iodide, or a groove binder Hoechst 3342, and the angular dependence of the intensity of two-photon excited fluorescence emitted by the dye was collected. The local orientation of DNA molecules in cholesteric and columnar LC phases was established on the basis of the relative angle between the transition dipole of the dye and the long axis of DNA helix. Three-dimensional images of the cholesteric phase were obtained making use of the intrinsic 3D resolving ability of two-photon microscopy. We also discuss the influence of dyes on the parameters of DNA LC phases and comment on advantages and limitations of the PSTPM technique in comparison with other LC characterization techniques.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Faculty of Chemistry, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland. joanna.olesiak@pwr.wroc.pl
authors.forename: Joanna
authors.initials: J
authors.lastname: Olesiak-Banska
authors.forename: Halina
authors.initials: H
authors.lastname: Mojzisova
authors.forename: Dominique
authors.initials: D
authors.lastname: Chauvat
authors.forename: Marcin
authors.initials: M
authors.lastname: Zielinski
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Matczyszyn
authors.forename: Patrick
authors.initials: P
authors.lastname: Tauc
authors.forename: Joseph
authors.initials: J
authors.lastname: Zyss
mesh_terms: D004247:DNA / Q000737:chemistry*; D021621:Imaging, Three-Dimensional; D007364:Intercalating Agents / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000379:methods; D008859:Microscopy, Polarization / Q000379:methods; D017785:Photons; D011419:Propidium / Q000737:chemistry; D012996:Solutions
chemical_list: D007364:Intercalating Agents; D012996:Solutions; D011419:Propidium; D004247:DNA