Teo Wei Zhe, Chng Elaine Lay Khim, Sofer Zdeněk, Pumera Martin
Division of Chemistry & Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore), Fax: (+65) 6791-1961.
Chemistry. 2014 Jul 28;20(31):9627-32. doi: 10.1002/chem.201402680. Epub 2014 Jun 26.
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.
涉及过渡金属二硫属化物（TMDs）的研究已经开展了数十年，近年来，许多研究聚焦于使用TMDs来合成碳纳米管、富勒烯以及石墨烯及其衍生物的无机类似物，最终目标是将这些材料应用于消费产品。鉴于这一上升趋势，我们研究了三种常见的剥离型TMDs（exTMDs），即二硫化钼（MoS2）、二硫化钨（WS2）和二硒化钨（WSe2）的细胞毒性，并将它们的毒理学效应与氧化石墨烯和卤化石墨烯进行比较，以查明这些石墨烯及其衍生物的无机类似物是否会表现出更好的生物相容性。在对人肺癌上皮细胞（A549）暴露于不同浓度的三种exTMDs 24小时后，使用甲基噻唑基二苯基溴化四氮唑（MTT）和水溶性四氮唑盐（WST-8）检测法进行细胞活力评估，结果表明，即使在高浓度下，MoS2和WS2纳米片对A549细胞的细胞毒性也非常低。另一方面，WSe2对A549细胞表现出剂量依赖性的毒理学效应，在最大浓度400μg mL-1时，细胞活力降至31.8%；WSe2表现出的较高细胞毒性可能与硫族元素的特性有关。与氧化石墨烯和卤化石墨烯相比，MoS2和WS2的危害性要小得多，而WSe2表现出相似程度的细胞毒性。未来的深入研究应以这项关于MoS2和WS2体外细胞毒性的首次研究为基础，以确保它们不会造成急性毒性。最后，纳米材料诱导的干扰控制实验表明，exTMDs在无细胞的情况下能够与MTT检测法的活力标记物发生反应，但不能与WST-8检测法发生反应。这表明MTT检测法不适用于测量exTMDs的细胞毒性，因为会得到夸大的结果，给人一种材料毒性较小的错误印象。
