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Cytotoxicity Effects of Graphene and Single-Wall Carbon Nanotubes in Neural Phaeochromocytoma-Derived PC12 Cells

Neurochemistry Laboratory, Division of Neurotoxicology, National Center for Toxicological Research, Food and Drug Administration, 3900 NCTR Road, Jefferson, Arkansas 72079, USA.
ACS Nano (Impact Factor: 12.88). 06/2010; 4(6):3181-6. DOI: 10.1021/nn1007176
Source: PubMed

ABSTRACT Graphitic nanomaterials such as graphene layers (G) and single-wall carbon nanotubes (SWCNT) are potential candidates in a large number of biomedical applications. However, little is known about the effects of these nanomaterials on biological systems. Here we show that the shape of these materials is directly related to their induced cellular toxicity. Both G and SWCNT induce cytotoxic effects, and these effects are concentration- and shape-dependent. Interestingly, at low concentrations, G induced stronger metabolic activity than SWCNT, a trend that reversed at higher concentrations. Lactate dehydrogenase levels were found to be significantly higher for SWCNT as compared to the G samples. Moreover, reactive oxygen species were generated in a concentration- and time-dependent manner after exposure to G, indicating an oxidative stress mechanism. Furthermore, time-dependent caspase 3 activation after exposure to G (10 microg/mL) shows evidence of apoptosis. Altogether these studies suggest different biological activities of the graphitic nanomaterials, with the shape playing a primary role.

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    • "In parallel to efforts directed at identifying new applications for carbon nanotubes (CNTs) and at improving ways to mass-produce them [1] [2], efforts are underway to examine health and ecological effects of these materials, as increasing production and use certainly will lead to release to the environment and biological exposure [3] [4] [5]. Of the several proposed processes used to explain toxicity of these materials, ''oxidative stress'' is recognized as one of the likely causes [6] [7] [8] [9] [10]. Oxidative stress presumably occurs through reactive oxygen species (ROS) generation, and while mechanisms of photo-induced ROS generation by CNTs has been reported [11] [12] [13], there is limited information on light-independent generation of ROS and the underlying mechanisms responsible for this generation [14]. "
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    • "However, in this type of toxicity, the key role is played by factors such as the duration of the culture and the graphene structure defined as the number of layers, shape, texture and its dimensions. [5] [8] It has been found that the most crucial factors that play an important role in the cell culture are the changes in the hydrophilic/hydrophobic nature of the substrate and its roughness.[7,9À11] With regard to the cytotoxic effects, what is of particular importance is the purity of the substrate, which is fundamentally different in products obtained from carbon *Corresponding author. "
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    • "Graphene is a monolayer carbon nano particle that consists of sp 2 hybridized carbon atoms arranged in hexagonal planar structures. Properties that have endeared this unique material to diverse applications are its exceptional mechanical strength (Young's modulus of 1 TPa, tensile strength of 20 GPa) [18] [19], excellent electrical (5000 S/m) [20] thermal conductivities and stability (~3000 W/m K) [21]. Therefore , it is logical to expect that incorporating graphene into polymeric matrices will improve the flammability and thermal conductivity of the host polymers significantly. "
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