Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Superresolution Optical Microscopy (focus session)

BP 7.7: Vortrag

Montag, 16. März 2015, 16:30–16:45, H 1028

Cryo-Fluorescence Microscopy of Single Molecules — •Weixing Li, Simon Stein, Ingo Gregor, and Joerg Enderlein — DPI, Georg-August-University Goettingen, Germany

The super-resolution fluorescence localization microscopy methods such as Stochastic Optical Reconstruction Microscopy (STORM), Photoactivation Localization Microscopy (PALM), or Ground State Depletion Imaging (GSDIM), routinely achieve a lateral image resolution of ~ 30 nm. This resolution is directly related to the number of photons emitted from a single fluorescent molecule and roughly scales with the invers square root of the detected photon number. Therefore, photo-bleaching is the fundamental bottleneck that limits the achievable resolution. One method to suppress photo-bleaching is to cool a sample down to cryogenic temperatures. For that purpose, we designed and built a dedicated cryostat suitable for single molecule fluorescence microscopy. The system is not only capable of cooling the sample to cryogenic temperatures, but gives also optical access to the sample for high-quality imaging with a conventional microscope employing an objective with high numerical aperture. Another important property of our system is its excellent mechanical stability, enabling long-time observations of samples over several hours with negligible drift. Using our system, we successfully performed photo-bleaching studies on single molecules showing a more than two order of magnitude enhancement in photo-stability, which results in an exceptional molecular localization accuracy in angstrom scale.