Cytotoxicity of exfoliated transition-metal dichalcogenides (MoS 2, WS2, and WSe2) is lower than that of graphene and its analogues

Wei Zhe Teo, Elaine Lay Khim Chng, Zdeněk Sofer, Martin Pumera

Research output: Contribution to journalArticle

169 Citations (Scopus)

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 μgmL-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 MoS 2 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. A matter of safety: An assessment on the in vitro cytotoxicity of three different exfoliated transition-metal dichalcogenides (exTMDs), namely, MoS2, WS2, and WSe2, has been conducted to determine if the exposure to this class of nanomaterials may have an adverse impact on our wellbeing should they be commercialized in the future.

Original languageEnglish
Pages (from-to)9627-9632
Number of pages6
JournalChemistry - A European Journal
Volume20
Issue number31
DOIs
Publication statusPublished - 2014 Jul 28

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Cytotoxicity
Graphene
Transition metals
Assays
Bromides
Nanostructured materials
Oxides
Chalcogens
Cells
Tetrazolium Salts
Fullerenes
Derivatives
Carbon Nanotubes
Consumer products
Nanosheets
Poisons
Biocompatibility
Toxicity
Carbon nanotubes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

Cite this

@article{b1e43e6ca41a4cca9bc9b32c14c6e0dc,
title = "Cytotoxicity of exfoliated transition-metal dichalcogenides (MoS 2, 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 μgmL-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 MoS 2 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. A matter of safety: An assessment on the in vitro cytotoxicity of three different exfoliated transition-metal dichalcogenides (exTMDs), namely, MoS2, WS2, and WSe2, has been conducted to determine if the exposure to this class of nanomaterials may have an adverse impact on our wellbeing should they be commercialized in the future.",
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Cytotoxicity of exfoliated transition-metal dichalcogenides (MoS 2, WS2, and WSe2) is lower than that of graphene and its analogues. / Teo, Wei Zhe; Chng, Elaine Lay Khim; Sofer, Zdeněk; Pumera, Martin.

In: Chemistry - A European Journal, Vol. 20, No. 31, 28.07.2014, p. 9627-9632.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cytotoxicity of exfoliated transition-metal dichalcogenides (MoS 2, WS2, and WSe2) is lower than that of graphene and its analogues

AU - Teo, Wei Zhe

AU - Chng, Elaine Lay Khim

AU - Sofer, Zdeněk

AU - Pumera, Martin

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Y1 - 2014/7/28

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