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Structural Defects Play a Major Role in the Acute Lung Toxicity of Multiwall Carbon Nanotubes: Physicochemical Aspects.

Authors :
UCL - MD/ESP - Ecole de santé publique
Fenoglio, Ivana
Greco, Giovanna
Tomatis, Maura
Muller, Julie
Raymundo-Pinero, Encarnacion
Beguin, François
Fonseca, Antonio
Nagy, Janos
Lison, Dominique
Fubini, Bice
UCL - MD/ESP - Ecole de santé publique
Fenoglio, Ivana
Greco, Giovanna
Tomatis, Maura
Muller, Julie
Raymundo-Pinero, Encarnacion
Beguin, François
Fonseca, Antonio
Nagy, Janos
Lison, Dominique
Fubini, Bice
Source :
Chemical research in toxicology, Vol. 21, no. 9, p. 1690-7 (2008)
Publication Year :
2008

Abstract

Carbon nanotubes (CNT) have been reported to elicit toxic responses in vitro and in vivo, ascribed so far to metal contamination, CNT length, degree of oxidation, or extent of hydrophilicity. To examine how structural properties may modulate the toxicity of CNT, one preparation of multiwall CNT has been modified (i) by grinding (introducing structural defects) and subsequently heating either in a vacuum at 600 degrees C (causing reduction of oxygenated carbon functionalities and reduction of metallic oxides) or in an inert atmosphere at 2400 degrees C (causing elimination of metals and annealing of defects) and (ii) by heating at 2400 degrees C in an inert atmosphere and subsequently grinding the thermally treated CNT (introducing defects in a metal-deprived carbon framework). The presence of framework and surface defects, metals, and oxygenated functionalities was monitored by means of a set of techniques, including micro-Raman spectroscopy, adsorption calorimetry, X-ray photoelectron spectroscopy, inductively coupled plasma mass spectrometry, and atomic emission spectroscopy. Contrary to traditional toxicants, such as asbestos, CNT may quench rather than generate oxygenated free radicals. The potential of the modified CNT to scavenge hydroxyl radicals was thus evaluated by means of electron spin resonance spectroscopy (spin trapping). The original ground material exhibited a scavenging activity toward hydroxyl radicals, which was eliminated by heating at 2400 degrees C but restored upon grinding. This scavenging activity, related to the presence of defects, appears to go paired with the genotoxic and inflammatory potential of CNT reported in the companion paper. Thus, defects may be one of the major factors governing the toxic potential of CNT.

Details

Database :
OAIster
Journal :
Chemical research in toxicology, Vol. 21, no. 9, p. 1690-7 (2008)
Notes :
English
Publication Type :
Electronic Resource
Accession number :
edsoai.on1130581436
Document Type :
Electronic Resource