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Zernike Institute for Advanced Materials Colloquium Stefan W. Hell


21 June 2012 FWN-Building 5111.0080, Nijenborgh 4, 9747 AG, Groningen
Speaker: Prof. Dr. Stefan W. Hell

Max-Planck-Institute for Biophysical Chemistry, Department of NanoBiophotonics, Göttingen, Germany

Title: Nanoscopy with focused light
Date: Thu Jun 21, 2012
Start: 16.00 (Doors open and coffee available at 15.30)
Location: FWN-Building 5111.0080


In STED microscopy1, fluorescent features are switched off by the STED beam, which confines the fluorophores to the ground state everywhere in the focal region except at a subdiffraction area of extent ) .

In RESOLFT microscopy2,3, the principles of STED have been expanded to fluorescence on-off-switching at low intensities I, by resorting to molecular switching mechanisms that entail low switching thresholds Is . An Is lower by many orders of magnitude is provided by reversibly switching the fluorophore to a long-lived dark (triplet) state2-4 or between a long-lived ‘fluorescence activated’ and ‘deactivated’ state2,5.

These alternative switching mechanisms entail an Is that is several orders of magnitude lower than in STED. In imaging applications, STED/RESOLFT enables fast recordings and the application to living cells, tissues, and even living animals6,7.

Starting from the basic principles of nanoscopy we will discuss recent developments8,9 with particular attention to RESOLFT and the recent nanoscale imaging of the brain of living mice7 by STED.

  1. Hell, S. W. & Wichmann, J. Breaking the diffraction resolution limit by stimulated-emission - stimulated-emission-depletion fluorescence microscopy. Opt Lett 19, 780-782, doi:10.1364/OL.19.000780 (1994).
  2. Hell, S. W. Toward fluorescence nanoscopy. Nat Biotechnol 21, 1347-1355 (2003).
  3. Hell, S. W., Jakobs, S. & Kastrup, L. Imaging and writing at the nanoscale with focused visible light through saturable optical transitions. Appl Phys A 77, 859-860 (2003).
  4. Hell, S. W. Far-Field Optical Nanoscopy. Science 316, 1153-1158 (2007).
  5. Hofmann, M., Eggeling, C., Jakobs, S. & Hell, S. W. Breaking the diffraction barrier in fluorescence microscopy at low light intensities by using reversibly photoswitchable proteins. PNAS 102, 17565-17569 (2005).
  6. Rankin, B. R. et al. Nanoscopy in a Living Multicellular Organism Expressing GFP. Biophys J 100, L63 - L65 (2011).
  7. Berning, S., Willig, K. I., Steffens, H., Dibaj, P. & Hell, S. W. Nanoscopy in a Living Mouse Brain. Science 335, 551 (2012).
  8. Grotjohann, T. et al. Diffraction-unlimited all-optical imaging and writing with a

photochromic GFP. Nature 478, 204-208 (2011).

  1. Brakemann, T. et al. A reversibly photoswitchable GFP-like protein with fluorescence

excitation decoupled from switching. Nat Biotechnol 29, 942-947 (2011). 

Last modified:22 October 2012 2.30 p.m.