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Updated: Aug 8, 2026
09:45
Fluorescence Lifetime Imaging of Molecular Rotors in Living Cells
Published on: February 9, 2012
A molecular rotor as viscosity sensor in aqueous colloid solutions
1University of Missouri-Columbia, Department of Biological Engineering, Columbia, MO 65211, USA.
Journal of Biomechanical Engineering
|September 3, 2004
Summary
Molecular rotors can determine fluid viscosity by measuring fluorescence. This study calibrated rotors for use as colloid solution viscosity probes, achieving high precision in viscosity measurements.
Area of Science:
- Physical Chemistry
- Materials Science
- Biophysics
Background:
- Molecular rotors exhibit fluorescence that changes with fluid viscosity, enabling non-mechanical viscosity measurements.
- Analysis focused on how viscosity-modulating macromolecules, significantly larger than rotor molecules, affect fluorescence.
- This work explores the application of molecular rotors in complex fluid environments.
Purpose of the Study:
- To investigate the suitability of hydrophilic molecular rotors as probes for determining the viscosity of colloid solutions.
- To establish a quantitative relationship between molecular rotor fluorescence and solution viscosity.
- To assess the precision of viscosity determination using molecular rotor fluorescence.
Main Methods:
- Fluorescence measurements of a molecular rotor in aqueous starch solutions (dextran and hydroxyethylstarch).
- Viscosity determination using a cone-and-plate viscometer for calibration.
- Analysis of fluorescence intensity and quantum yield in relation to solution viscosity.
Main Results:
- A power-law relationship was observed between emission intensity and viscosity in dextran solutions.
- Biexponential fluorescence behavior was noted in hydroxyethylstarch solutions, with viscosity-dependent exponents.
- Viscosity was accurately backcalculated from fluorescence intensity with an average precision of 2.2%.
Conclusions:
- Hydrophilic molecular rotors are effective probes for colloid solution viscosity.
- Calibration is necessary for accurate viscosity measurements in specific colloid solutions.
- Molecular rotors offer a non-mechanical method for viscosity determination in complex fluids.
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