•OH and O2•- Generation in Aqueous C60 and C70 Solutions by Photoirradiation:  An EPR Study

Yamakoshi, Yoko; Sueyoshi, Shoko; Fukuhara, Kiyoshi; Miyata, Naoki; Masumizu, Toshiki; Kohno, Masahiro

doi:10.1021/ja9823969

Cited by 148 publications

(108 citation statements)

References 31 publications

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“…These workers claimed that the changes mediated by C 60 complexed to γ-CyD were predominantly due to singlet oxygen while that caused by C 60 (OH) 18 was mainly due to radical species. Our photochemical studies (Figures 4-6) indicate that irradiated fullerenes can generate both singlet oxygen and superoxide in water.…”

Section: Discussionmentioning

confidence: 99%

“…Our previous studies (10) have shown that a variety of watersoluble fullerenes can efficiently generate singlet oxygen ( 1 O 2 ) upon irradiation via energy transfer (type II photochemical mechanism) from the excited triplet of fullerene to oxygen (11)(12)(13). There are also reports that photoirradiation of fullerenes in aqueous systems results in the production of the corresponding radical anions (C 60 ·-) followed by generation of superoxide (O 2 ·-) and hydroxyl radical ( · OH) via electron transfer (type I photochemical mechanism), especially in the presence of electron donors (such as NADH or amines) (14)(15)(16)(17)(18). These two photochemical mechanisms, typically present during photodynamic therapy (PDT), constitute the main pathways for the photoinduced toxicity of fullerenes (19).…”

Section: Introductionmentioning

confidence: 99%

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Pristine (C₆₀) and Hydroxylated [C₆₀(OH)₂₄] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Zhao

Bilski

et al. 2008

Chem. Res. Toxicol.

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The increasing use of fullerene nanomaterials has prompted widespread concern over their biological effects. Herein, we have studied the phototoxicity of γ-cyclodextrin bicapped pristine C 60 [(γ-CyD) 2 /C 60 ] and its water-soluble derivative C 60 (OH) 24 toward human keratinocytes. Our results demonstrated that irradiation of (γ-CyD) 2 /C 60 or C 60 (OH) 24 in D 2 O generated singlet oxygen with quantum yields of 0.76 and 0.08, respectively. Irradiation (>400 nm) of C 60 (OH) 24 generated superoxide as detected by the EPR spin trapping technique; superoxide generation was enhanced by addition of the electron donor nicotinamide adenine dinucleotide (reduced) (NADH). During the irradiation of (γ-CyD) 2 /C 60 , superoxide was generated only in the presence of NADH. Cell viability measurements demonstrated that (γ-CyD) 2 /C 60 was about 60 times more phototoxic to human keratinocytes than C 60 (OH) 24 . UVA irradiation of human keratinocytes in the presence of (γ-CyD) 2 /C 60 resulted in a significant rise in intracellular protein-derived peroxides, suggesting a type II mechanism for phototoxicity. UVA irradiation of human keratinocytes in the presence of C 60 (OH) 24 produced diffuse intracellular fluorescence when the hydrogen peroxide probe Peroxyfluor-1 was present, suggesting a type I mechanism. Our results clearly show that the phototoxicity induced by (γ-CyD) 2 /C 60 is mainly mediated by singlet oxygen with a minor contribution from superoxide, while C 60 (OH) 24 phototoxicity is mainly due to superoxide.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pristine (C₆₀) and Hydroxylated [C₆₀(OH)₂₄] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Zhao

Bilski

et al. 2008

Chem. Res. Toxicol.

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“…[21][22][23][24] Furthermore, as has recently been demonstrated, functionalized fullerenes in aqueous solution can also sensitize reactive oxygen species (ROS). [25][26][27] Both major photoreaction pathways are schematically shown in Figure 4a. The Type I mechanism involves electron or hydrogen-atom transfer between the excited photosensitizer triplet state and a substrate.…”

Section: Esr Study Of the Photophysical Propertiesmentioning

confidence: 99%

Spectroscopic and Photophysical Properties of a Highly Derivatized C₆₀ Fullerol

Vileno

Marcoux

Lekka

et al. 2005

Adv Funct Materials

127

151

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Hydroxylated C60 molecules, also called fullerols, are a class of water‐soluble fullerenes. Here we report the synthesis in acidic conditions of a highly derivatized fullerol (up to 36 carbons per C60 are oxidized). Spectroscopic investigations (X‐ray photoelectron spectroscopy and infrared absorption) highlight the coexistence of both acidic and basic forms for the hydroxyl addends of derivatized C60. pH titrimetry reveals that, at millimolar concentrations, only ten protons per fullerol molecule are labile. Such a low value, as compared to 36 hydroxyl groups, is explained by the formation of clusters. A UV‐vis absorption study performed over a large range of concentrations also points to the aggregation phenomenon. Moreover, this study shows that the clusters of fullerols appear at relatively low (micromolar) concentrations. An electron spin resonance (ESR) study, based on the attack of singlet oxygen (1Δg) on 2,2,6,6‐tetramethyl‐4‐piperidinol (TMP‐OH), has proved the potential of hydroxylated C60 for performing efficient generation of singlet oxygen in aqueous solution. ESR measurements, which allow detection and quantification of 1Δg, have also revealed the generation of reactive oxygen species (ROS). The yield of generation of 1Δg and ROS is strongly correlated to the concentration of fullerol, thus also pointing to the aggregation of fullerol molecules. Exposing glioblastoma cells to oxidative stress in the presence of hydroxylated C60 and visible light has also been performed. Atomic force microscopy is used to monitor the relevant diminishment of the Young's modulus values for cells exposed to the oxidative stress. These results point to a possible application field of fullerols for performing bio‐oxidations.

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“…The reason for molecular oxygen and hydrogen peroxide generation is photochemical reactions on carbon nanotubes or fullerene surface in aqueous suspension under photoirradiation. [18] In Fig. 2(b), we display the experimental data (dots, dashed curve) and calculated curve (solid line) of RIKES spectra in the SWNT aqueous suspension.…”

Section: Resultsmentioning

confidence: 99%

“…The SWNT samples are synthesized by the electric arc discharge technique [13,15] in a helium atmosphere under a pressure of 650 Torr. Cobalt and carbon electrodes were used as the catalyst and carbon source, respectively.…”

Section: Methodsmentioning

confidence: 99%

Raman‐induced Kerr effect spectroscopy of single‐wall carbon nanotubes aqueous suspensions in the range 0.1–10 and 100–250 cm⁻¹

Бункин

Першин

2011

J Raman Spectroscopy

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Here, we study a low (less than 0.1 µg/ml) concentration aqueous suspension of single-wall carbon nanotubes (SWNTs) by Raman-induced Kerr effect spectroscopy (RIKES) in the spectral bands 0.1-10 and 100-250 cm −1 . This method is capable of carrying out direct investigation of SWNT hydration layers. A comparison of RIKES spectra of SWNT aqueous suspension and that of milli-Q water shows a considerable growth in the intensity of low wavenumber Raman modes. These modes in the 0.1-10 cm −1 range are attributed to the rotational transitions of H 2 O 2 and H 2 O molecules. We explain the observed intensity increase as due to the production of hydrogen peroxide and the formation of a low-density depletion layer on the water-nanotube interface. A few SWNT radial breathing modes (RBM)are observed (ω RBM = 118.5, 164.7 and 233.5 cm −1 ) in aqueous suspension, which allows us to estimate the SWNT diameters (∼2.0, 1.5, and 1 nm, respectively).

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•OH and O₂^•- Generation in Aqueous C₆₀ and C₇₀ Solutions by Photoirradiation: An EPR Study

Cited by 148 publications

References 31 publications

Pristine (C₆₀) and Hydroxylated [C₆₀(OH)₂₄] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Pristine (C₆₀) and Hydroxylated [C₆₀(OH)₂₄] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Spectroscopic and Photophysical Properties of a Highly Derivatized C₆₀ Fullerol

Raman‐induced Kerr effect spectroscopy of single‐wall carbon nanotubes aqueous suspensions in the range 0.1–10 and 100–250 cm⁻¹

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•OH and O2•- Generation in Aqueous C60 and C70 Solutions by Photoirradiation: An EPR Study

Cited by 148 publications

References 31 publications

Pristine (C60) and Hydroxylated [C60(OH)24] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Pristine (C60) and Hydroxylated [C60(OH)24] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Spectroscopic and Photophysical Properties of a Highly Derivatized C60 Fullerol

Raman‐induced Kerr effect spectroscopy of single‐wall carbon nanotubes aqueous suspensions in the range 0.1–10 and 100–250 cm−1

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Product

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•OH and O₂^•- Generation in Aqueous C₆₀ and C₇₀ Solutions by Photoirradiation: An EPR Study

Pristine (C₆₀) and Hydroxylated [C₆₀(OH)₂₄] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Pristine (C₆₀) and Hydroxylated [C₆₀(OH)₂₄] Fullerene Phototoxicity towards HaCaT Keratinocytes: Type I vs Type II Mechanisms

Spectroscopic and Photophysical Properties of a Highly Derivatized C₆₀ Fullerol

Raman‐induced Kerr effect spectroscopy of single‐wall carbon nanotubes aqueous suspensions in the range 0.1–10 and 100–250 cm⁻¹