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Pressure effect on the nonradiative process of thioflavin-T
Nadav Amdursky1, Rinat Gepshtein, Yuval Erez
1Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel.
The Journal of Physical Chemistry. A
|May 19, 2011
Summary
Hydrostatic pressure slows the nonradiative decay of thioflavin-T (ThT) by increasing solvent viscosity. This study reveals a linear correlation between viscosity and ThT
Area of Science:
- Photophysics
- Chemical Kinetics
- Materials Science
Background:
- Thioflavin-T (ThT) is a fluorescent dye used in amyloid detection.
- Understanding ThT's photophysical properties is crucial for its applications.
- Solvent viscosity significantly impacts molecular nonradiative decay rates.
Purpose of the Study:
- To investigate the effect of hydrostatic pressure on the nonradiative decay of ThT.
- To elucidate the relationship between solvent viscosity and ThT's nonradiative rate.
- To explore the mechanism behind viscosity-dependent nonradiative decay in ThT.
Main Methods:
- Time-resolved emission spectroscopy was used to study ThT in 1-propanol, 1-butanol, and 1-pentanol.
- Hydrostatic pressures up to 2.4 GPa were applied using a diamond-anvil cell.
- Solvent viscosity was systematically varied to observe changes in ThT's nonradiative rate.
Main Results:
- The nonradiative rate constant (k(nr)) of ThT decreased with increasing hydrostatic pressure.
- A linear correlation was observed between decreasing k(nr) (increasing nonradiative lifetime) and increasing solvent viscosity.
- k(nr) decreased significantly, with lifetimes extending from picoseconds to nanoseconds across the studied alcohols.
Conclusions:
- Increased hydrostatic pressure enhances solvent viscosity, leading to a slower nonradiative decay of ThT.
- The viscosity dependence of k(nr) is attributed to the excited-state rotational dynamics of ThT's two-ring system.
- These findings provide insights into the photophysical behavior of ThT under varying environmental conditions.
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