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Particle and Fibre Toxicology

, 13:34

First Online: 21 June 2016Received: 13 August 2015Accepted: 14 June 2016DOI: 10.1186-s12989-016-0145-5

Cite this article as: Roberts, J.R., Mercer, R.R., Stefaniak, A.B. et al. Part Fibre Toxicol 2015 13: 34. doi:10.1186-s12989-016-0145-5

Abstract

BackgroundGraphene, a monolayer of carbon, is an engineered nanomaterial ENM with physical and chemical properties that may offer application advantages over other carbonaceous ENMs, such as carbon nanotubes CNT. The goal of this study was to comparatively assess pulmonary and systemic toxicity of graphite nanoplates, a member of the graphene-based nanomaterial family, with respect to nanoplate size.

MethodsThree sizes of graphite nanoplates 20 μm lateral Gr20, 5 μm lateral Gr5, and <2 μm lateral Gr1 ranging from 8–25 nm in thickness were characterized for difference in surface area, structure,, zeta potential, and agglomeration in dispersion medium, the vehicle for in vivo studies. Mice were exposed by pharyngeal aspiration to these 3 sizes of graphite nanoplates at doses of 4 or 40 μg-mouse, or to carbon black CB as a carbonaceous control material. At 4 h, 1 day, 7 days, 1 month, and 2 months post-exposure, bronchoalveolar lavage was performed to collect fluid and cells for analysis of lung injury and inflammation. Particle clearance, histopathology and gene expression in lung tissue were evaluated. In addition, protein levels and gene expression were measured in blood, heart, aorta and liver to assess systemic responses.

ResultsAll Gr samples were found to be similarly composed of two graphite structures and agglomerated to varying degrees in DM in proportion to the lateral dimension. Surface area for Gr1 was approximately 7-fold greater than Gr5 and Gr20, but was less reactive reactive per m. At the low dose, none of the Gr materials induced toxicity. At the high dose, Gr20 and Gr5 exposure increased indices of lung inflammation and injury in lavage fluid and tissue gene expression to a greater degree and duration than Gr1 and CB. Gr5 and Gr20 showed no or minimal lung epithelial hypertrophy and hyperplasia, and no development of fibrosis by 2 months post-exposure. In addition, the aorta and liver inflammatory and acute phase genes were transiently elevated in Gr5 and Gr20, relative to Gr1.

ConclusionsPulmonary and systemic toxicity of graphite nanoplates may be dependent on lateral size and-or surface reactivity, with the graphite nanoplates > 5 μm laterally inducing greater toxicity which peaked at the early time points post-exposure relative to the 1–2 μm graphite nanoplate.

KeywordsGraphene-based nanomaterials Pulmonary exposure Cardiovascular toxicity Lung toxicity Particle size Electronic supplementary materialThe online version of this article doi:10.1186-s12989-016-0145-5 contains supplementary material, which is available to authorized users.

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Autor: Jenny R. Roberts - Robert R. Mercer - Aleksandr B. Stefaniak - Mohindar S. Seehra - Usha K. Geddam - Ishrat S. Chaudhu

Fuente: https://link.springer.com/







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