Singlet oxygen luminescence quantum yields in organic solvents and water

Losev, A. P.; Byteva, I. M.; Gurinovich, G. P.

doi:10.1016/0009-2614(88)87025-8

Cited by 82 publications

(48 citation statements)

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“…μM counts counts to the value of Φ P =4.4×10 −3 obtained by Krasnovsky,14) and distinctly smaller than those of Φ P =1.8×10 −2 reported by Losev et al, 15) or Φ P =4.9×10 −2 obtained by Schmidt et al 16) However, in his first investigation, Krasnovsky determined the value of Φ P =5×10 −5 in CCl 4 from corrected emission spectra of the sensitizer protoporphyrin and 1 O 2 , 13) and later corrected his result to Φ P =4.4×10 −3 using tetraphenylporphine (TPP), which is more photochemically stable. The much lower value obtained in his first study can thus be explained by the poor photostability of the sensitizer.…”

Section: Resultsmentioning

confidence: 56%

“…A large change in sensitivity can result in serious errors in corrections for emission spectra over the wide spectral range from 650 to 1270 nm. In the investigation by Losev et al, 15) their value of Φ P =1.8×10 −2 in CCl 4 was determined using LiNd phosphate glass with one of the emission bands at 1320 nm as a quantum yield standard. The quantum yield of the Nd glass, however, was only an estimate that was calculated from the luminescence lifetime and the known radiative lifetime of the glass.…”

Section: Resultsmentioning

confidence: 99%

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Determination of Phosphorescence Quantum Yield of Singlet Oxygen O₂(¹Δ_g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

et al. 1998

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§1. IntroductionSinglet oxygen 1 O 2 is generally accepted to be a highly reactive intermediate in the processes leading to photochemical damage in biological systems, 1) including tumor destruction in photodynamic therapy. 2) Photosensitization is one of the most common methods of generating singlet oxygen, 3) and the photophysical processes of its formation have been studied extensively in a variety of solvents. 4-11) Detection of 1 O 2 phosphorescence at around 1270 nm is the best technique for investigating the various photochemical and photobiological processes involving the 1 O 2 , since this method does not disturb the system under study. 12) However, conflicting results have been presented in the studies on the absolute quantum yield Φ P of 1 O 2 phosphorescence. For example, Φ P values in CCl 4 have been variously determined as 5×10 −5 , 13) 4.4×10 −3 , 14) 1.8×10 −2 , 15) and 4.9×10 −2 . 16) A major reason for these conflicting Φ P values may be the low sensitivity of the apparatus used in the near-IR spectral region of 1 O 2 phosphorescence. The photomultipliers with an S-1 response are almost blind in the near-IR region at around 1270 nm, and conventional germanium semiconductors have insufficient sensitivity to produce reliable data in the near-IR region. In addition to these technical problems, probable source of error in the quantum yield measurements might be related to the emission standards for known quantum yields and to the photostability of the sensitizer employed.The use of photomultipliers sensitive in the near-IR spectral region have solved the above technical problems and enabled a highly sensitive photon-counting technique. Employing a photon counter coupled with a photomultiplier sensitive in the near-IR, Shimizu et al. succeeded in obtaining both time-and spectral-resolved measurements of 1 O 2 emission in water 17) and provided spectral and kinetic evidence for the generation of 1 O 2 photosensitized by aromatic amino acids. 18) Quinine bisulfate (QBS) in 1.0N sulfuric acid has been a nearly perfect compound as a quantum yield standard because of its photostability in solution. 19) In addition, this compound is not quenched by oxygen, and there is no significant overlap between its absorption and emission spectra. The aromatic ketone phenalenone (PH) has been reported to be one of the most efficient photosensitizers that is photochemically stable and, when used as a reference sensitizer, readily soluble in most solvents, even water. 9,20,21) Taking the above facts into account, in the present paper we measured the phosphorescence quantum yield of 1 O 2 sensitized by PH in air-saturated CCl 4 using a photon counter coupled with a near-IR-sensitive photomultiplier. A steady-state excitation was employed to measure both the millisecond phosphorescence of 1 O 2 in CCl 4 and the nanosecond fluorescence of QBS in 1.0N H 2 SO 4 . The phosphorescence quantum yield of Φ P in CCl 4 was determined by comparative measurements of the areas under the corrected emission spectra of 1 O 2 and QBS in 1...

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Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 99%

Determination of Phosphorescence Quantum Yield of Singlet Oxygen O₂(¹Δ_g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

et al. 1998

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“…In H 2 O no emission was observed, which is due to the much lower solubility of oxygen in water than in organic solvents 42 and very low quantum yield of singlet oxygen emission ( ϕ ~ 10 -7 ). 43 In water, singlet oxygen emission is efficiently quenched by OH vibrations as well as by the emission re-absorption by the OH vibrational overtone. 44,45 As a result, the lifetime of singlet oxygen in water is very short, only 3.5 μ s. 46 On the other hand, in D 2 O the lifetime is significantly longer, i.e.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of phototoxicity of dendritic porphyrin-based phosphorescent oxygen probes: an in vitro study

Ceroni

Lebedev

Marchi

et al. 2011

Photochem Photobiol Sci

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Biological oxygen measurements by phosphorescence quenching make use of exogenous phosphorescent probes, which are introduced directly into the medium of interest (e.g. blood or interstitial fluid) where they serve as molecular sensors for oxygen. The byproduct of the quenching reaction is singlet oxygen, a highly reactive species capable of damaging biological tissue. Consequently, potential probe phototoxicity is a concern for biological applications. Herein, we compared the ability of polyethyleneglycol (PEG)-coated Pd tetrabenzoporphyrin (PdTBP)-based dendritic nanoprobes of three successive generations to sensitize singlet oxygen. It was found that the size of the dendrimer has practically no effect on the singlet oxygen sensitization efficiency in spite of the strong attenuation of the triplet quenching rate with an increase in the dendrimer generation. This unexpected result is due to the fact that the lifetime of the PdTBP triplet state in the absence of oxygen increases with dendritic generation, thus compensating for the concomitant decrease in the rate of quenching. Nevertheless, in spite of their ability to sensitize singlet oxygen, the phosphorescent probes were found to be non-phototoxic when compared with the commonly used photodynamic drug Photofrin in a standard cell-survival assay. The lack of phototoxicity is presumably due to the inability of PEGylated probes to associate with cell surfaces and/or penetrate cellular membranes. In contrast, conventional photosensitizers bind to cell components and act by generating singlet oxygen inside or in the immediate vicinity of cellular organelles. Therefore, PEGylated dendritic probes are safe to use for tissue oxygen measurements as long as the light doses are less than or equal to those commonly employed in photodynamic therapy.

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“…This has provided a means of directly monitoring the generation and reactivity of 02(lAg). The large amount of data covering many various sensitizer and substrate molecules has allowed some conclusions to be drawn on basic questions such as the solvent dependency of the lifetime of 02('A,) (Merkel and Kearns, 1972;Hurst and Schuster, 1983;Rodgers, 1983;Schmidt and Brauer, 1987;Lin et al, 1988;Schmidt, 1989), the radiative lifetime of O,( lag) (Krasnovsky, 1981;Gorman et al, 1987;Scurlock and Ogilby, 1987;Losev et al, 1988;Schmidt et al, 1989;Schmidt and Afshari, 1990;Gorman et al, 1991), the parameters which determine the efficiency of 02(IAg) generation by sensitizers (Redmond and Braslavsky, 1988b), and the reactivity of substrates with this highly oxidative excited species (see Gorman and Rodgers, 1989).…”

Section: Introductionmentioning

confidence: 99%

ENHANCEMENT OF THE SENSITIVITY OF RADIATIVE and NON‐RADIATIVE DETECTION TECHNIQUES IN THE STUDY OF PHOTOSENSITIZATION BY WATER SOLUBLE SENSITIZERS USING A REVERSE MICELLE SYSTEMS*,†

Redmond

1991

Photochem & Photobiology

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The study of photosensitization processes in aqueous solution is complicated by the unsuit‐ability of water as solvent for the commonly used techniques for monitoring radiative and non‐radiative relaxation processes. The infrared luminescence method is hampered by the relatively weak intensity of emission and short lifetime of singlet molecular oxygen, O2(1Δg), in water. Photoacoustic and photothermal detection of the dominant non‐radiative relaxation process for O2(1Δg) is also inhibited by the unfavorable physico‐chemical properties of water which reduce the sensitivities of these techniques for the study of sensitizers in aqueous with respect to non‐aqueous media. Such problems have been alleviated by incorporating the sensitizer in the aqueous core of aerosol OT reverse micelles. It is demonstrated that the sensitivity of both radiative and non‐radiative detection depends not on the local environment of the sensitizer but on the overall composition of the medium, which, in the case of reverse micelle solutions, is predominantly hydrocarbon. This produces a 4.5 and 6‐fold enhancement of the sensitivity of luminescence and optoacoustic detection, respectively, in comparison to purely aqueous solution. The utility of the method is demonstrated for Rose Bengal, where quantum yields of intersystem crossing (φisc) of 0.78 (LIOAC) and singlet oxygen generation (φδ) of 0.81 (LIOAC) and 0.80 (TRLD) were measured. Phenazine was also studied for comparative purposes and to corroborate values obtained for Rose Bengal.

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Singlet oxygen luminescence quantum yields in organic solvents and water

Cited by 82 publications

References 5 publications

Determination of Phosphorescence Quantum Yield of Singlet Oxygen O₂(¹Δ_g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

Determination of Phosphorescence Quantum Yield of Singlet Oxygen O₂(¹Δ_g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

Evaluation of phototoxicity of dendritic porphyrin-based phosphorescent oxygen probes: an in vitro study

ENHANCEMENT OF THE SENSITIVITY OF RADIATIVE and NON‐RADIATIVE DETECTION TECHNIQUES IN THE STUDY OF PHOTOSENSITIZATION BY WATER SOLUBLE SENSITIZERS USING A REVERSE MICELLE SYSTEMS*,†

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Singlet oxygen luminescence quantum yields in organic solvents and water

Cited by 82 publications

References 5 publications

Determination of Phosphorescence Quantum Yield of Singlet Oxygen O 2( 1Δ g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

Determination of Phosphorescence Quantum Yield of Singlet Oxygen O 2( 1Δ g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

Evaluation of phototoxicity of dendritic porphyrin-based phosphorescent oxygen probes: an in vitro study

ENHANCEMENT OF THE SENSITIVITY OF RADIATIVE and NON‐RADIATIVE DETECTION TECHNIQUES IN THE STUDY OF PHOTOSENSITIZATION BY WATER SOLUBLE SENSITIZERS USING A REVERSE MICELLE SYSTEMS*,†

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Determination of Phosphorescence Quantum Yield of Singlet Oxygen O₂(¹Δ_g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride

Determination of Phosphorescence Quantum Yield of Singlet Oxygen O₂(¹Δ_g) Photosensitized by Phenalenone in Air-Saturated Carbon Tetrachloride