Radiative Transitions of Singlet Oxygen: New Tools, New Techniques and New Interpretations

Keszthelyi, Tamás; Weldon, Dean; Andersen, Thomas N.; Poulsen, Tina D.; Mikkelsen, Kurt V.; Ogilby, Peter R.

doi:10.1562/0031-8655(1999)070<0531:rtoson>2.3.co;2

Cited by 12 publications

(16 citation statements)

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“…The instrumentation and methods used to (1) monitor O 2 (a 1 Δ g ) → O 2 (X 3 Σ g − ) phosphorescence at ~1275 nm in time‐resolved experiments and quantify photosensitized O 2 (a 1 Δ g ) quantum yields and O 2 (a 1 Δ g ) lifetimes , and (2) perform time‐resolved triplet absorption experiments are described in the references cited. For the O 2 (a 1 Δ g ) studies, miniSOG was irradiated with the 1 kHz output of a fs laser at 418 nm, and all O 2 (a 1 Δ g ) experiments were performed in 1 cm path length cuvettes under conditions where the sample absorbance at the irradiation wavelength did not exceed ~0.1.…”

Section: Methodsmentioning

confidence: 99%

Oxygen‐Dependent Photochemistry and Photophysics of “MiniSOG,” a Protein‐Encased Flavin

Pimenta

Jensen

Breitenbach

et al. 2013

Photochem & Photobiology

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102

150

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Selected photochemical and photophysical parameters of flavin mononucleotide (FMN) have been examined under conditions in which FMN is (1) solvated in a buffered aqueous solution, and (2) encased in a protein likewise solvated in a buffered aqueous solution. The latter was achieved using the so-called "mini Singlet Oxygen Generator" (miniSOG), an FMN-containing flavoprotein engineered from Arabidopsis thaliana phototropin 2. Although FMN is a reasonably good singlet oxygen photosensitizer in bulk water (ϕΔ = 0.65 ± 0.04), enclosing FMN in this protein facilitates photoinitiated electron-transfer reactions (Type-I chemistry) at the expense of photosensitized singlet oxygen production (Type-II chemistry) and results in a comparatively poor yield of singlet oxygen (ϕΔ = 0.030 ± 0.002). This observation on the effect of the local environment surrounding FMN is supported by a host of spectroscopic and chemical trapping experiments. The results of this study not only elucidate the behavior of miniSOG but also provide useful information for the further development of well-characterized chromophores suitable for use as intracellular sensitizers in mechanistic studies of reactive oxygen species.

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Section: Methodsmentioning

confidence: 99%

Oxygen‐Dependent Photochemistry and Photophysics of “MiniSOG,” a Protein‐Encased Flavin

Pimenta

Jensen

Breitenbach

et al. 2013

Photochem & Photobiology

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102

150

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“…The basic features of the instrumentation and methods employed in the present study have been described previously (21, 34–36). Briefly, singlet oxygen was generated in a photosensitized process upon irradiation of TMPyP incorporated in the sample of interest.…”

Section: Methodsmentioning

confidence: 99%

5,10,15,20-Tetrakis(N-Methyl-4-Pyridyl)-21H,23H-Porphine (TMPyP) as a Sensitizer for Singlet Oxygen Imaging in Cells: Characterizing the Irradiation-dependent Behavior of TMPyP in a Single Cell†

Snyder

Lambert

Ogilby

2006

Photochem Photobiol

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Singlet molecular oxygen, a1Delta(g), can be detected from a single cell by its weak 1270 nm phosphorescence (a1Delta(g)-->X3Sigma(g)-) upon irradiation of the photosensitizer 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) incorporated into the cell. The behavior of this sensitizer in a cell, and hence the behavior of the associated singlet oxygen phosphorescence signal, depends on the conditions under which the sample is exposed to light. Upon irradiation of a neuron freshly incubated with TMPyP, the intensity of TMPyP fluorescence initially increases and there is a concomitant increase in the singlet oxygen phosphorescence intensity from the cell. These results appear to reflect a photoinduced release of TMPyP bound to DNA in the nucleus of the cell, where TMPyP tends to localize, and the subsequent relocalization of TMPyP to a different microenvironment in the cell. Upon prolonged irradiation of the cell, TMPyP photobleaches and there is a corresponding decrease in the singlet oxygen phosphorescence intensity from the cell. The data reported herein provide insight into key factors that can influence photosensitized singlet oxygen experiments performed on biological samples.

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“…An explicit quantum mechanical solution for the M‐O 2 complex, both in its initial state i and final state f , provides an appropriate description of the respective electronic distributions that derive from short range interactions. The additional effects of solvation are then readily incorporated in the functional description of the surrounding dielectric medium through terms derived from the optical ɛ op and static ɛ st dielectric constants (74).…”

Section: Perturbed and Solvated Oxygenmentioning

confidence: 99%

“…The effect of solvent on the O 2 (a 1 Δ g ) → O 2 (X 3 Σ g − ) emission spectrum was an issue addressed by the experimental community in the late 1980s and early 1990s (54,55,103). Monitoring the effect of solvent on the O 2 (b 1 Σ g + ) → O 2 (a 1 Δ g ) emission spectrum provided additional experimental challenges, but this was accomplished shortly thereafter (67,74,104). Finally, and most challenging of all, were experiments to record O 2 (a 1 Δ g ) → O 2 (b 1 Σ g + ) absorption spectra (67,74,105–107).…”

Section: Perturbed and Solvated Oxygenmentioning

confidence: 99%

“…Monitoring the effect of solvent on the O 2 (b 1 Σ g + ) → O 2 (a 1 Δ g ) emission spectrum provided additional experimental challenges, but this was accomplished shortly thereafter (67,74,104). Finally, and most challenging of all, were experiments to record O 2 (a 1 Δ g ) → O 2 (b 1 Σ g + ) absorption spectra (67,74,105–107). The data obtained portray a consistent picture.…”

Section: Perturbed and Solvated Oxygenmentioning

confidence: 99%

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Overview of Theoretical and Computational Methods Applied to the Oxygen‐Organic Molecule Photosystem

Paterson

Christiansen

Jensen

et al. 2006

Photochem & Photobiology

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110

158

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Radiative Transitions of Singlet Oxygen: New Tools, New Techniques and New Interpretations

Cited by 12 publications

References 0 publications

Oxygen‐Dependent Photochemistry and Photophysics of “MiniSOG,” a Protein‐Encased Flavin

Oxygen‐Dependent Photochemistry and Photophysics of “MiniSOG,” a Protein‐Encased Flavin

5,10,15,20-Tetrakis(N-Methyl-4-Pyridyl)-21H,23H-Porphine (TMPyP) as a Sensitizer for Singlet Oxygen Imaging in Cells: Characterizing the Irradiation-dependent Behavior of TMPyP in a Single Cell†

Overview of Theoretical and Computational Methods Applied to the Oxygen‐Organic Molecule Photosystem

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