Iodide as a Fluorescence Quencher and Promoter—Mechanisms and Possible Implications
| Autor: | Jerker Widengren, Tor Sandén, Andriy Chmyrov |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Iodide
Biophysics Fluorescence correlation spectroscopy 02 engineering and technology 010402 general chemistry Photochemistry Physical Chemistry 01 natural sciences Rhodamine chemistry.chemical_compound Materials Chemistry Fysik Physical and Theoretical Chemistry Triplet state CORRELATION SPECTROSCOPY CONFOCAL MICROSCOPY TRIPLET-STATES DYES EXCITATION KINETICS CELLS Fluorescent Dyes Fysikalisk kemi chemistry.chemical_classification Quenching (fluorescence) Rhodamines Potassium Iodide Models Theoretical 021001 nanoscience & nanotechnology Fluorescence Biofysik 0104 chemical sciences Surfaces Coatings and Films Kinetics Spectrometry Fluorescence Intersystem crossing chemistry Physical Sciences Quantum Theory 0210 nano-technology Visible spectrum |
| Zdroj: | The Journal of Physical Chemistry B. 114:11282-11291 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp103837f |
| Popis: | In this work, fluorescence correlation spectroscopy (FCS) was used to investigate the effects of potassium iodide (KI) on the electronic-state population kinetics of a range of organic dyes in the visible wavelength range. Apart from a heavy atom effect promoting intersystem crossing to the triplet states in all dyes, KI was also found to enhance the triplet-state decay rate by a charge-coupled deactivation. This deactivation was only found for dyes with excitation maximum in the blue range, not for those with excitation maxima at wavelengths in the green range or longer. Consequently, under excitation conditions sufficient for triplet state formation, KI can promote the triplet state buildup of one dye and reduce it for another, red-shifted dye. This anticorrelated, spectrally separable response of two different dyes to the presence of one and the same agent may provide a useful readout for biomolecular interaction and microenvironmental monitoring studies. In contrast to the typical notion of KI as a fluorescence quencher, the FCS measurements also revealed that when added in micromolar concentrations KI can act as an antioxidant, promoting the recovery of photo-oxidized fluorophores. However, in millimolar concentrations KI also reduces intact, fluorescently viable fluorophores to a considerable extent. In aqueous solutions, for the dye Rhodamine Green, an optimal concentration of KI of approximately 5 mM can be defined at which the fluorescence signal is maximized. This concentration is not high enough to allow full triplet state quenching. Therefore, as a fluorescence enhancement agent, it is primarily the antioxidative properties of KI that play a role. QC 20101206 |
| Databáze: | OpenAIRE |
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