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SUMMARY: dSTORM: Super-resolution imaging with small organic fluorophores 
 - Prof. Dr. Markus Sauer\, Department of Biotechnology and Biophysics\, Un
 iversity of Wuerzburg
DTSTART:20100526T103000Z
DTEND:20100526T113000Z
UID:TALK23400@talks.cam.ac.uk
CONTACT:Duncan Simpson
DESCRIPTION:Super-resolution fluorescence imaging methods based on reversi
 ble photoswitching of fluorophores with subsequent localization currently 
 develop to promising tools for cellular imaging. We introduce a general ap
 proach for multicolor super-resolution fluorescence imaging based on photo
 switching of standard small organic fluorophores. Photoswitching of organi
 c rhodamine and oxazine fluorophores\, i.e. the reversible transition from
  a fluorescent to a non-fluorescent state in aqueous buffers exploits the 
 formation of long-lived radical anions through reaction with thiol compoun
 ds (e.g. glutathione or mercaptoethylamine) and repopulation of the single
 t ground state by reaction with molecular oxygen. The achievable resolutio
 n and herewith the ability to resolve a structural feature depends not onl
 y on the brightness of the fluorophores\, but also on the labeling density
  and on the stability or lifetime of the non-fluorescent dark state. Here\
 , we discuss how the ratio of off- and on-switching of a fluorophore affec
 ts resolution. We compare experimental data with theoretical simulations a
 nd present a strategy to customize photoswitching characteristics to achie
 ve optimal optical resolution.\nWe unravel the underlying switching mechan
 ism and demonstrate super-resolution imaging with different commercially a
 vailable organic fluorophores with ~ 20 nm optical resolution in fixed and
  living cells. Combining the genetic labeling approach with small\, bright
  and photostable organic fluorophores represents the method of choice for 
 future super-resolution imaging and precision colocalization experiments.\
 n
LOCATION:Seminar Room\, Centre for Physics of Medicine (PoM)
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