Evaluation of the Carbon Nanostructures Toxicity as a Function of Their Dimensionality Using Model Organisms: a Review

Nanotechnology has been widely used, with nanomaterials being applied in several technologies. However, little is known about the real toxicological risk that can be caused by nanomaterials. These materials can be divided according to their dimensionalities. The current classification schemes for nanostructured materials are based on these dimensionalities, generally as zero (0D), one (1D), two (2D), and three dimensions (3D). Toxicological studies to present broad and consistent information on nanomaterials toxicity mechanisms, in vitro and in vivo studies in several experimental models are necessary. Thus, this short review presents the toxicological potential of carbon nanomaterials, divided by their dimensionality, in the main in vitro and in vivo experimental models, especially alternative models. As a result, it was possible to observe that the toxicity of carbon nanomaterials does not vary according to the dimensionality of 0D, 1D, and 2D materials. For these materials, it is not possible to infer a direct relationship between dimensionality and toxicity. However, recent studies have shown that three-dimensional graphene species tend to have less toxicity than materials with a smaller number of dimensions. Finally, it was possible to note the importance of using several experimental models, especially alternative models, in order to increase the understanding of toxicity mechanisms of carbon nanomaterials.