Reactivity of carbon nanotubes: Free radical generation or scavenging activity?

Fenoglio, Ivana; Tomatis, Maura; Lison, Dominique; Muller, Julie; Fonseca, A.; Nagy, J.B.; Fubini, Bice

doi:10.1016/j.freeradbiomed.2005.11.010

Cited by 291 publications

(208 citation statements)

References 44 publications

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“…carbon black, 37 multi-walled carbon nanotubes, 38 and fullerenes. 39 Because inactivation takes place only with the milled samples and not with mixtures, we assume that mechanism 1 is the most likely one. Mechanisms 2 could also take place but only with particles close one to the other.…”

Section: Discussionmentioning

confidence: 99%

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

Ghiazza

Tomatis

Doublier

et al. 2012

Chem. Res. Toxicol.

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In order to evaluate the effect of carbonaceous materials on the pathogenic activity of quartz dusts, mixtures of carbon soot (1% and 10%) and quartz (Min-U-Sil ) have been prepared, then milled so to attain an intimate association of carbon and the quartz surface. Both cellular and cell-free tests show that carbon associated to quartz completely inhibits the typical free radical generation of quartz dusts (through Fenton activity and homolytic cleavage of a C-H bond) and suppresses the oxidative stress and inflammation induced by quartz alone on MH-S murine macrophage cells (lipid peroxidation, nitric oxide release, tumour necrosis factor-α synthesis). Cytotoxic response to quartz is also largely reduced. An extremely pure quartz milled with 10% of soot showed inactivating effects on the adverse reactions to quartz similar to Min-U-Sil quartz. None of these effects takes place when the same experiments are carried out with mechanically mixed samples, which suggests that carbon acts not just as a radical quencher, but because of its association to the quartz surface.4

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Section: Discussionmentioning

confidence: 99%

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

Ghiazza

Tomatis

Doublier

et al. 2012

Chem. Res. Toxicol.

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“…Purified CNTs were found to be generally more photoactive, producing singlet oxygen and superoxide, while little or no photoactivity was observed for raw CNTs 22, 23, 24. CNTs can also act as scavengers of hydroxyl or superoxide radicals,74, 75, 76, 77 or undergo photochemical transformations (e.g., decarbonilation) as in the case of oxidized multiwalled CNTs 24…”

Section: Origin Of Photoactivity Of Nanoporous Carbonsmentioning

confidence: 99%

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

Bandosz

Ania

2018

Advanced Science

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Even though, owing to the complexity of nanoporous carbons' structure and chemistry, the origin of their photoactivity is not yet fully understood, the recent works addressed here clearly show the ability of these materials to absorb light and convert the photogenerated charge carriers into chemical reactions. In many aspects, nanoporous carbons are similar to graphene; their pores are built of distorted graphene layers and defects that arise from their amorphicity and reactivity. As in graphene, the photoactivity of nanoporous carbons is linked to their semiconducting, optical, and electronic properties, defined by the composition and structural defects in the distorted graphene layers that facilitate the exciton splitting and charge separation, minimizing surface recombination. The tight confinement in the nanopores is critical to avoid surface charge recombination and to obtain high photochemical quantum yields. The results obtained so far, although the field is still in its infancy, leave no doubts on the possibilities of applying photochemistry in the confined space of carbon pores in various strategic disciplines such as degradation of pollutants, solar water splitting, or CO2 mitigation. Perhaps the future of photovoltaics and smart‐self‐cleaning or photocorrosion coatings is in exploring the use of nanoporous carbons.

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“…Significant damage to the CNTs is observed during pretreatment at 30% cmc, but not at 300% cmc (Figure 7f). The general observation that the I D /I G + ratio is affected by ultrasonication may be related to CNT damage via ROS attack 32 . The lower level of damage at 300% cmc is rationalized by the protective coating of the excess surfactant on the CNT surface, which will naturally form as the cmc point is surpassed.…”

Section: Resultsmentioning

confidence: 99%

Influence of Acoustic Cavitation on the Controlled Ultrasonic Dispersion of Carbon Nanotubes

et al. 2013

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Ultrasonication is the most widely used technique for the dispersion of a range of nanomaterials, but the intrinsic mechanism which leads to stable solutions is poorly understood with procedures quoted in the literature typically specifying only extrinsic parameters such as nominal electrical input power and exposure time. Here we present new insights into the dispersion mechanism of a representative nanomaterial, single-walled carbon nanotubes (SW-CNTs), using a novel upscalable sonoreactor and an in situ technique for the measurement of acoustic cavitation activity during ultrasonication. We distinguish between stable cavitation, which leads to chemical modification of the surface of the CNTs, and inertial cavitation, which favors CNT exfoliation and length reduction. Efficient dispersion of CNTs in aqueous solution is found to be dominated

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Reactivity of carbon nanotubes: Free radical generation or scavenging activity?

Cited by 291 publications

References 44 publications

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

Influence of Acoustic Cavitation on the Controlled Ultrasonic Dispersion of Carbon Nanotubes

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