Role of reactive oxygen species in the toxicity of two-dimensional nanomaterials: A study on layered Ti3C2 MXenes

Abstract

Two-dimensional (2D) materials, such as MXenes and graphene, are tested as catalysts, sensors, and nanomedicine, but their safety and biocompatibility are poorly understood. In this study, Ti3C2 MXenes (single-layer and multilayer) and graphene oxide are prepared to evaluate their inflammatory potential in vivo and in vitro using the read-across approach. Pulmonary exposure of the test materials in mice led to significant dose-dependent increases in several toxicity endpoints of bronchoalveolar lavage fluid. The correlation of the oxidative potential of the test materials and the toxicity endpoints shows that both the intrinsic and intracellular oxidative potentials of 2D materials are key factors for the inflammation and damage of the plasma membrane. Scanning electron microscopy and in vitro studies using the differentiated THP-1 macrophage-like cells support this finding. Furthermore, the toxicity of test items is reduced when treated with N-acetyl cysteine, a scavenger for reactive oxygen species; this finding further supports the oxidative stress paradigm proposed in this study. This oxidative stress paradigm may apply to 2D materials in general and improve the understanding the toxicity mechanism of such materials, which would facilitate the design of safer functional 2D materials.