Differences in the Toxicological Potential of 2D versus Aggregated Molybdenum Disulfide in the Lung

2D molybdenum disulfide (MoS 2 ) has distinct optical and electronic properties compared to aggregated MoS 2 , enabling wide use of these materials for electronic and biomedical applications. However, the hazard potential of MoS 2 has not been studied extensively. Here, a comprehensive analysis of the pulmonary hazard potential of three aqueous suspended forms of MoS 2 —aggregated MoS 2 (Agg‐MoS 2 ), MoS 2 exfoliated by lithiation (Lit‐MoS 2 ), and MoS 2 dispersed by Pluronic F87 (PF87‐MoS 2 )—is presented. No cytotoxicity is detected in THP‐1 and BEAS‐2B cell lines. However, Agg‐MoS 2 induces strong proinflammatory and profibrogenic responses in vitro. In contrast, Lit‐ and PF87‐MoS 2 have little or no effect. In an acute toxicity study in mice, Agg‐MoS 2 induces acute lung inflammation, while Lit‐MoS 2 and PF87‐MoS 2 have little or no effect. In a subchronic study, there is no evidence of pulmonary fibrosis in response to all forms of MoS 2 . These data suggest that exfoliation attenuates the toxicity of Agg‐MoS 2 , which is an important consideration toward the safety evaluation and use of nanoscale MoS 2 materials for industrial and biological applications.