Monitoring Kinetics of Highly Environment Sensitive States of Fluorescent Molecules by Modulated Excitation and Time-Averaged Fluorescence Intensity Recording
by
Tor Sandén(Experimental Biomolecular Physics, KTH)
→
Europe/Stockholm
FA32
FA32
Description
A concept is described for how the kinetics of photo-induced, transient, long-lived, non- or weakly fluorescent states of fluorophores can be extracted from the time-averaged fluorescence by using time-modulated excitation. This concept exploits the characteristic variation of the population of these states with the modulation settings and circumvents the need for time-resolution in the fluorescence detection. Further it combines the single-molecule sensitivity of fluorescence detection with the environmental responsiveness obtainable from long-lived transient states and yet does not impose any constraints on the concentration of the sample molecules that can be measured.
As a first experimental verification of the approach, we have shown how the triplet state parameters of the fluorophore Rhodamine 6G in different aqueous environments can be extracted. We demonstrate that the concept is fully compatible with low time-resolution detection by a CCD camera. Altogether, the concept opens for the possibility of transient state monitoring or imaging on an automated parallel scale.