| AVS 59th Annual International Symposium and Exhibition | |
| Biomaterials Plenary Session | Sunday Sessions |
| Session BP+AS-SuA |
| Session: | Biomaterials Plenary - Bioimaging: In Vacuo, In Vitro, In Vivo |
| Presenter: | S.W. Hell, Max-Planck-Institut für Biophysikalische Chemie, Germany |
| Correspondent: | Click to Email |
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 microscopy,2,3 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 or between a long-lived ‘fluorescence activated’ and ‘deactivated’ state.2,5 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 animals.6,7
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, 780-782, doi:10.1364/OL.19.000780 (1994).
2 Hell, S. W. Toward fluorescence nanoscopy, 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, 859-860 (2003).
4 Hell, S. W. Far-Field Optical Nanoscopy, 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, 17565-17569 (2005).
6 Rankin, B. R. Nanoscopy in a Living Multicellular Organism Expressing GFP, L63 - L65 (2011).
7 Berning, S., Willig, K. I., Steffens, H., Dibaj, P. & Hell, S. W. Nanoscopy in a Living Mouse Brain, 551 (2012).
8 Grotjohann, T. Diffraction-unlimited all-optical imaging and writing with a photochromic GFP, 204-208 (2011).
9 Brakemann, T. A reversibly photoswitchable GFP-like protein with fluorescence excitation decoupled from switching, 942-947 (2011).