Fluorescence correlation spectroscopy of triplet states in solution: a theoretical and experimental study

Widengren, Jerker; Mets, Uelo; Rigler, Rudolf

doi:10.1021/j100036a009

Cited by 727 publications

(905 citation statements)

References 9 publications

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“…For the first group of dyes (in order of increasing absorption wavelengths: FITC, Rh6G, TMR, LRhB, ATTO590, Alexa594, ATTO610, Alexa610 and Alexa633) a prominent increase of triplet state build-up was observed with increasing KI concentrations. This response is well in agreement with that previously observed for KI on Rh6G 17 . For the second group of fluorophores however (in order of increasing absorption wavelengths: Alexa488, ATTO488, RhGr and Rh123), the effect of KI was the opposite -with increasing KI concentrations a distinct decrease of the triplet state build-up was observed.…”

Section: Selective Quenching Of the Fluorophore Triplet States By Kisupporting

confidence: 93%

“…In FCS, for a fluorescent molecule diffusing into and out of the detection volume, and at the same time undergoing transitions to and from its lowest triplet state, the time dependent part of the correlation function can be expressed as 17 :…”

Section: Theorymentioning

confidence: 99%

“…Iodide is well known to enhance intersystem crossing in organic fluorophores, in particular by the so-called heavy atom effect [20][21][22] . Previously, it has been shown for several dyes that addition of KI leads to a strong enhancement of the triplet state population 17,18 . We show that for many dyes absorbing/emitting in the blue/green range addition of KI instead leads to a reduction of the triplet state population.…”

Section: Introductionmentioning

confidence: 99%

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Iodide as a Fluorescence Quencher and Promoter—Mechanisms and Possible Implications

2010

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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 chargecoupled 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 build-up of one dye and reduce it for another, red-shifted dye. This anti-correlated, 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 micro-environmental 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 anti-oxidant, promoting the recovery of photo-oxidized fluorophores. However, in millimolar concentrations 2 KI also reduces intact, fluorescently viable fluorophores to a considerable extent. In aqueous solutions, 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 anti-oxidative properties of KI that play a role.

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Section: Selective Quenching Of the Fluorophore Triplet States By Kisupporting

confidence: 93%

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Iodide as a Fluorescence Quencher and Promoter—Mechanisms and Possible Implications

2010

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“…where a is the equivalent bond length of the monomer, ϕ is the polymer volume fraction, r s is the radius of solute, r f is the radius of polymer chain, C ∞ is the characteristic ratio of polymer, χ is the Flory-Huggins polymer/solvent interaction parameter, D g is the diffusion coefficient of solute in gel, and D 0 is the diffusion coefficient of solute in water calculated from MD simulation and verified by literature [38,102,72,73,74].…”

Section: Amsden's Obstruction Scaling Theorymentioning

confidence: 73%

“…For consistency with the rhodamine molecule, the force field parameters for the acrylate cross-linker, chloride and sodium ions are from the CHARMM27 force field [61] and summarized in [72,73,74]. For cross LJ interaction parameters between ions and water, and between PEG chain and CHARMM atoms, we followed Patra et al [75] and Zheng et al [76] respectively and used Lorentz-Berthelot combination rules.…”

Section: Force Field Parameters For Cross-linker and Ionsmentioning

confidence: 99%

Effect of Cross-Linking on the Diffusion of Water, Ions, and Small Molecules in Hydrogels

2009

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Understanding the diffusion of small molecules in hydrogel system is of major importance in a variety of applications including drug delivery systems, tissue engineering and contact lens. Cross-linking density of hydrogels has been commonly used to tune key parameters like mesh size and molecular weight between cross-linkers, in order to change macroscopic properties of hydrogels. In this thesis, molecular dynamics investigations of chemically-cross-linked poly(ethylene glycol) (PEG) hydrogels are reported with the aim of exploring the diffusion properties of water, ions, and rhodamine within the polymer at the molecular level.The water structure and diffusion properties were studied at various cross-linking densities with molecular weights of the chains ranging from 572 to 3400. As the cross-linking density is increased, the water diffusion decreases and the slowdown in diffusion is more severe at the polymer-water interface. The water diffusion at various cross-linking densities is correlated with the water hydrogen bonding dynamics. The diffusion of ions and rhodamine also decreased as the cross-linking density is increased. The variation of diffusion coefficient with cross-linking density is related to the variation of water content at different cross-linking densities.Comparison of simulation results and obstruction scaling theory for hydrogels showed similar trends.ii To Father and Mother.iii

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Fluorescence correlation spectroscopy: molecular recognition at the single molecule level

Craenenbroeck

Engelborghs

2000

J. Mol. Recognit.

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Fluorescence correlation spectroscopy (FCS) is a fluorescence microscopy technique that allows the study of molecular interactions in extremely low volumes, at nanomolar concentrations, even when binding is not accompanied by a fluorescence change. It can be applied directly in living cells. FCS clearly considerably extends the possibilities of the classical techniques used in molecular recognition studies and can be considered to belong to a growing group of techniques that allow detection at the single molecule level. In this review, several applications of FCS, both in vitro and in vivo, will be discussed.

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Fluorescence correlation spectroscopy of triplet states in solution: a theoretical and experimental study

Cited by 727 publications

References 9 publications

Iodide as a Fluorescence Quencher and Promoter—Mechanisms and Possible Implications

Iodide as a Fluorescence Quencher and Promoter—Mechanisms and Possible Implications

Effect of Cross-Linking on the Diffusion of Water, Ions, and Small Molecules in Hydrogels

Fluorescence correlation spectroscopy: molecular recognition at the single molecule level

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