Regensburg 2004 – wissenschaftliches Programm
CPP 9.6: Vortrag
Montag, 8. März 2004, 15:15–15:30, H 38
Optical Polarization Tomography: A new method to determine the three-dimensional orientation of single molecules — •Michael Prummer1, Horst Vogel1, Beate Sick2, Bert Hecht3, and Urs P. Wild4 — 1Institute of Biomolecular Sciences, EPFL, CH-1015 Lausanne — 2DNA-Array Facility, University of Lausanne, CH-1015 Lausanne — 3Institute of Physics, University of Basel, CH-4056 Basel — 4Physical Chemistry Laboratory, ETH-Hönggerberg, CH-8093 Zürich
We apply the concept of tomography to polarization-sensitive optical microscopy of single fluorophores to determine the three-dimensional orientation of molecular absorption dipoles with isotropic sensitivity. Wide-field microscopy provides the opportunity to monitor simultaneously three-dimensional rotation and two-dimensional translation of many molecules in parallel. For orientation determination the molecules are illuminated from different directions of incidence with linearly polarized light. In each exposure the excitation along a particular projection of the absorption dipole on the electric field leads to a distinct fluorescence intensity. Five exposures are sufficient to determine the full orientation of the fluorophores.