Cytotoxicity of Exfoliated Transition‐Metal Dichalcogenides (MoS₂, WS₂, and WSe₂) is Lower Than That of Graphene and its Analogues

Abstract

Studies involving transition-metal dichalcogenides (TMDs) have been around for many decades and in recent years, many were focused on using TMDs to synthesize inorganic analogues of carbon nanotubes, fullerene, as well as graphene and its derivatives with the ultimate aim of employing these materials into consumer products. In view of this rising trend, we investigated the cytotoxicity of three common exfoliated TMDs (exTMDs), namely MoS2 , WS2 , and WSe2 , and compared their toxicological effects with graphene oxides and halogenated graphenes to find out whether these inorganic analogues of graphenes and derivatives would show improved biocompatibility. Based on the cell viability assessments using methylthiazolyldiphenyl-tetrazolium bromide (MTT) and water-soluble tetrazolium salt (WST-8) assays on human lung carcinoma epithelial cells (A549) following a 24 h exposure to varying concentrations of the three exTMDs, it was concluded that MoS2 and WS2 nanosheets induced very low cytotoxicity to A549 cells, even at high concentrations. On the other hand, WSe2 exhibited dose-dependent toxicological effects on A549 cells, reducing cell viability to 31.8 % at the maximum concentration of 400 μg mL(-1) ; the higher cytotoxicity displayed by WSe2 might be linked to the identity of the chalcogen. In comparison with graphene oxides and halogenated graphenes, MoS2 and WS2 were much less hazardous, whereas WSe2 showed similar degree of cytotoxicity. Future in-depth studies should be built upon this first work on the in vitro cytotoxicity of MoS2 and WS2 to ensure that they do not pose acute toxicity. Lastly, nanomaterial-induced interference control experiments revealed that exTMDs were capable of reacting with MTT assay viability markers in the absence of cells, but not with WST-8 assay. This suggests that the MTT assay is not suitable for measuring the cytotoxicity of exTMDs because inflated results will be obtained, giving false impressions that the materials are less toxic.

Cytotoxicity of Group 5 Transition Metal Ditellurides (MTe2; M=V, Nb, Ta)

“…By comparing our data with those reported for the widely used Group 6 TMDs (namely MoS 2 ,WS 2 ,and WSe 2 ) [63] under similarconditions (such as undergoing a2 4h treatment of materials with A549 cells), we found that the Group 5t ransition metal ditellurides are generally more toxic than the Group 6T MDs.H owevera n exception was observed in WSe 2 ,w here it is more toxic than the Group 5t ransition metal ditellurides, with only VTe 2 being more toxic than WSe 2 (Table 1).…”

Molybdenum disulfide/graphene oxide nanocomposites show favorable lung targeting and enhanced drug loading/tumor-killing efficacy with improved biocompatibility

“…For MoS 2 , it is relatively more biocompatible than GO when comparing their in vitro and in vivo toxicity, because MoS 2 is rather inactive to biomolecules. 80,81 Considered together, these findings signified the improved biocompatibility of MoS 2 /GO nanocomposites for potential biomedical applications. Figure 9 Pro-inflammatory responses elicited by diverse materials in J774A.1 cells.…”

In Vivo Long‐Term Biodistribution, Excretion, and Toxicology of PEGylated Transition‐Metal Dichalcogenides MS2 (M = Mo, W, Ti) Nanosheets

“…At the in vitro level, it was found that the cytotoxicity of MoS 2 , WS 2 , and WSe 2 nanosheets appeared to be low to different cell lines 15, 18, 32, 33. On the other hand, in our previous reports about the use of polyethylene glycol (PEG) functionalized TMDCs for in vivo imaging and therapy applications, we have uncovered that PEGylated MoS 2 and WS 2 showed no appreciable acute toxicity to the treated mice at our tested dose 16, 20, 23, 34.…”