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Updated: Jul 13, 2026

Conducting Multiple Imaging Modes with One Fluorescence Microscope
Published on: October 28, 2018
Reversible photoswitching enables single-molecule fluorescence fluctuation spectroscopy at high molecular
C Eggeling1, M Hilbert, H Bock
1Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany. ceggeli@gwdg.de
Abstract:
We demonstrate that photoswitchable markers enable fluorescence fluctuation spectroscopy at high molecular concentration. Reversible photoswitching allows precise control of the density of fluorescing entities, because the equilibrium between the fluorescent ON- and the dark OFF-state can be shifted through optical irradiation at a specific wavelength. Depending on the irradiation intensity, the concentration of the ON-state markers can be up to 1,000 times lower than the actual concentration of the labeled molecular entity. Photoswitching expands the range of single-molecule detection based experiments such as fluorescence fluctuation spectroscopy to large entity concentrations in the micromolar range.
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