S E M I N A R 

FLUORESCENCE BLINKING IN FLUOROPHORES MONITORED BY FLUORESCENCE
CORRELATION SPECTROSCOPY 

Jerker Widengren 

Exp. Biomol. Physics / Applied Physics, Royal Inst. Technology (KTH) Stockholm, Sweden 

Utorak, 4 septembar, 2012 g. u 14 h u Biblioteci Instituta 

Abstract 

In FCS there are many ways by which molecular dynamic processes can be
monitored. One useful strategy is to analyse fluorescence fluctuations
arising due to a dynamic process taking place, which switches the
fluorescence of the studied molecules on and off. In this presentation
it will be discussed how FCS can be used to extract information from
molecular dynamic processes that change the fluorescence brightness of
the analysed molecules. It will be shown how FCS in combination with ion
sensitive fluorophores allow direct monitoring of ion exchange at a
molecular level, at equilibrium, with no perturbations, and with
negligible buffer effects from the fluorophores themselves. Further, it
is shown how FCS offers a straightforward means to monitor the
population kinetics of photo-induced, non-fluorescent transient states
of fluorophores. Knowledge about the population kinetics of these states
is important for the optimization of the fluorescence signal in single
molecule experiments, but can also provide complementary dimensions of
fluorescence-based information.