In postgraphene two-dimensional materials (2DMs), MoS2 has attracted increasing attention in the biomedical field due to its excellent physicochemical properties. However, the toxicity and biocompatibility evaluation of MoS2 is not fully addressed. Herein, chitosan functionalized MoS2 (CS-MoS2) nanosheets, which showed perfect dispersibility and stability performances, were synthesized and characterized. We found that CS-MoS2 nanosheets inhibited the viability of human dermal fibroblasts (HDFs) moderately while causing cell membrane instability, ROS generation, and DNA damage in a dosage-dependent manner. CS-MoS2 nanosheets did not induce significant changes in the cell morphologies, but they seemed to impair the cell division of HDFs. CS-MoS2 nanosheets (100 μg/mL) activated EGFR and induced reactive oxygen species, Smad, and IL-1, which in turn led to cell inflammation and apoptosis. Furthermore, HDFs showed cellular stress responses when they were exposed to low concentrations of CS-MoS2 nanosheets (25 and 100 μg/mL) because most of the intracellular metabolites such as amino acids were induced at 25 μg/mL but were inhibited at 100 μg/mL. Pyroglutamic acid, phosphoric acid, and inositol might be used as biomarkers for evaluating the toxicity of CS-MoS2 nanosheets. Additionally, 100 μg/mL CS-MoS2 nanosheets inhibited glutathione metabolism and induced the imbalance of cellular redox homeostasis. It further suppressed the tricarboxylic acid cycle and other metabolic pathways, causing insufficient supply of substrates and energy for HDFs. These findings will fuel the risk assessment of MoS2 and other 2DMs and guide the safe material design and 2DM applications.

Molybdenum disulfide (MoS 2 ), one of the next-generation two-dimensional materials (2DMs), has attracted increasing attention due to its unique physicochemical properties. However, the aquatic toxicity of dispersible MoS 2 is still unknown. Herein, we synthesized chitosan functionalized MoS 2 (CS-MoS 2 ) micro-sheets with a satisfying water-dispersible performance. The average length and width of the asprepared CS-MoS 2 micro-sheets were 5.04 mm and 3.12 mm, respectively, and they had a pristine 2H polymorph. The toxicity of CS-MoS 2 micro-sheets was assessed by investigating the organs, gills and liver of adult zebrafish. We found that exposure to high concentrations of CS-MoS 2 micro-sheets

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In this study, sulfated polysaccharides extracted from Laminaria japonica were degraded by free radicals to obtain low molecular weight fucoidan (LMWF). The in vivo and in vitro effects of LMWF on bleomycin-treated pulmonary fibrosis mice and TGF-treated A549 cells, respectively, were evaluated, and the role of antioxidant activity was assessed. H&E, Masson’s trichrome, and Sirius red staining results showed that bleomycin induced obvious pathological changes and collagen deposition in the lung tissue of mice. However, LMWF effectively inhibited collagen deposition, and based on immunohistochemistry analyses, LMWF can also inhibit the expression of fibrosis markers. At the same time, LMWF could regulate related antioxidant factors in the lung tissue of pulmonary fibrosis mice and reduce the pressure of oxidative stress. Moreover, LMWF could improve the morphology of cells induced with TGF, which confirmed that LMWF could inhibit fibrosis via antioxidant activity modulation.

MoS2, a kind of two-dimensional material with unique performances, has been widely used in many fields. However, an in-depth understanding of its toxicity is still needed, let alone its effects on the environmental microorganism. Herein, we used different methods, including metabolomics technology, to investigate the influence of bulk MoS2 (BMS) on yeast cells. The results indicated that high concentrations (1 mg/L and more) of BMS could destroy cell membrane and induce ROS accumulation. When exposed to a low concentration of BMS (0.1 mg/L), the intracellular concentrations of many metabolites (e.g., fumaric acid, lysine) increased. However, most of their concentrations descended significantly as the yeast cells were treated with BMS of high concentrations (1 mg/L and more). Metabolomics analysis further revealed that exposure to high concentrations of BMS could significantly affect some metabolic pathways such as amino acid and citrate cycle related metabolism. These findings will be beneficial for MoS2 toxicity assessment and further applications.