Regensburg 2010 – scientific programme

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BP: Fachverband Biologische Physik

BP 19: Membranes and Vesicles

BP 19.7: Talk

Wednesday, March 24, 2010, 11:45–12:00, H43

Exploring the Nanoscale: Dynamics of Lipid Rafts Revealed by STED Fluorescence Fluctuation Spectroscopy — •Veronika Mueller, Christian Ringemann, Rebecca Medda, Christian Eggeling, and Stefan Hell — Max-Planck-Institute for Biophysical Chemistry, Department of NanoBiophotonics, Am Fassberg 11, 37077 Goettingen, Germany

The study of molecular dynamics at the single-molecule level with fluorescence far-field optics offers new detailed insights into scientific problems, especially in living cells. Unfortunately, the resolution of common far-field techniques is limited to about 200nm in the lateral direction by diffraction. In recent years, several concepts such as stimulated emission depletion microscopy (STED) have been successfully applied to overcome the diffraction barrier. We present the combination of high resolution STED microscopy with different fluorescence fluctuation techniques providing the unique ability to study molecular dynamics with high spatial (<40nm) and temporal resolution (<1ms) in living cells. Using fluorescence correlation spectroscopy (FCS), we were able to explore single-molecule dynamics in up to 70-fold reduced focal volumes on two-dimensional samples such as lipid membranes with excellent signal-to-noise ratios. Special attention is drawn to inhomogeneous lipid diffusion on the plasma membrane of living cells. This new technique provides the possibility to non-invasively record molecular time traces and fluctuation data in continuously tuneable nanoscale focal areas and thus offers a powerful new approach to study the dynamics of biomolecules in living cell membranes.