Berlin 2005 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

AKB: Biologische Physik

AKB 200: Poster Session II

AKB 200.69: Poster

Dienstag, 8. März 2005, 17:00–19:00, Poster TU C

A versatile two-photon fluorescence laser scanning microscope for single molecule applications — •Zdeněk Petrášek and Petra Schwille — Biotechnologisches Zentrum der TU Dresden; Institut für Biophysik; Tatzberg 47 - 51; 01307 Dresden; Germany

An imaging system with optical beam scanning, two-photon excitation and fluorescence detection has been constructed. The setup consists of a Ti:Sapph laser and a commercial inverted microscope to which a home-built scanning and detection unit is attached. The fluorescence signal can be detected in two channels with the light separation based on wavelength or polarization. The time-resolved detection allows simultaneous measurement of fluorescence decay kinetics (sub-ns timescale) and FCS (sub-µ s to >s timescale) with the access to the complete photon sequence. The combination of imaging, pulsed excitation and fast detection allows fluorescence lifetime imaging (FLIM) to be performed.

The design focus has been on the freedom of control over the scan mirror movement. An arbitrary scanning pattern can be programmed, thus allowing scanning-FCS techniques to be employed. Scanning-FCS is especially suitable for investigation of slowly diffusing or stationary chromophores (FCS, cross-correlation). Since it is the laser beam and not the sample stage that is being moved, mechanical stability of the sample is maintained.