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Fluorescence Lifetime Imaging of Molecular Rotors in Living Cells
Published on: February 9, 2012
High-resolution intracellular viscosity measurement using time-dependent fluorescence anisotropy.
Wesley C Parker1, Nilay Chakraborty, Regina Vrikkis
1Department of Physics and Optical Science, University of North Carolina at Charlotte, Center for Optical Communications and Optoelectronics, 9201 University City Blvd. Charlotte, NC 28223, USA.
Optics Express
|August 20, 2010
Summary
This study quantifies cytoplasmic viscosity in mouse macrophage cells using a novel confocal-scanning epifluorescence microscope. The findings reveal intracellular viscosity ranges from 1.00 to 2.21 cP, offering insights into cellular biophysics.
Area of Science:
- Biophysics
- Cell Biology
- Microscopy
Background:
- Cytoplasmic viscosity is a critical biophysical parameter influencing cellular functions.
- Accurate measurement of intracellular viscosity at specific locations remains challenging.
Purpose of the Study:
- To develop and apply a low-cost, high-resolution method for determining intracytoplasmic viscosity.
- To map viscosity variations within specific locations of J774 mouse macrophage cells.
Main Methods:
- Utilized a homebuilt laser confocal-scanning epifluorescence microscope with submicron resolution.
- Employed time-dependent fluorescence anisotropy measurements of 8-hydroxyperene-1,3,6-trisulfonic acid (HPTS).
- Applied global deconvolution techniques to calculate rotational correlation times and infer viscosity.
Main Results:
- Rotational correlation times of HPTS ranged from 0.186 ns to 0.411 ns.
- Calculated cytoplasmic viscosities varied from 1.00 ± 0.03 cP to 2.21 ± 0.05 cP.
- Demonstrated viscosity heterogeneity at specific intracytoplasmic locations.
Conclusions:
- The developed microscopy technique provides accurate, localized measurements of cytoplasmic viscosity.
- Intracellular viscosity in J774 mouse macrophages exhibits a measurable range.
- This method offers a cost-effective approach for probing cellular biophysical properties.
