Fluorescence-based Broad Dynamic Range Viscosity Probes
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Updated: May 5, 2026

Fluorescence Lifetime Imaging of Molecular Rotors in Living Cells
Published on: February 9, 2012
Anatoliy Dragan1, August E Graham1, Chris D Geddes2
1Institute of Fluorescence and Department of Chemistry and Biochemistry, The Columbus Center, University of Maryland Baltimore County, 701 East Pratt Street, Baltimore, MD, 21202, USA.
Abstract:
We introduce two new fluorescent viscosity probes, SYBR Green (SG) and PicoGreen (PG), that we have studied over a broad range of viscosity and in collagen solutions. In water, both dyes have low quantum yields and excited state lifetimes, while in viscous solvents or in complex with DNA both parameters dramatically (300-1000-fold) increase. We show that in log-log scale the dependence of the dyes' quantum yield vs. viscosity is linear, the slope of which is sensitive to temperature. Application of SG and PG, as a fluorescence-based broad dynamic range viscosity probes, to the life sciences is discussed.
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