Since MoS2 has a layered structure, the properties of MoS2 thin films are significantly linked to the number of their layers . For example, the in-plane stiffness and breaking strength of monolayer MoS2 is higher than that of bulk MoS2 crystals . When the number of the MoS2 layers increases, the inter-layer van der Waals forces within MoS2 start to significantly suppress vibrations, which is the main reason why bulk MoS2 has a higher restoring force than monolayer MoS2 . Bulk MoS2 is a semiconductor material with an indirect band gap of 1.2 eV, and is often used as a photocatalyst, but also as a dry lubricant. A monolayer of MoS2, on the other hand, has a 1.9 eV direct band gap and possesses prominent electro- and photoluminescent properties . Moreover, it is generally believed that the toxicity of 2D layered MoS2 depends on its defect density, exfoliation parameters and chemical composition . Since the layer number can affect the surface area, defects and edge parameters of the MoS2 nanosheets, it has been found that the toxicity of MoS2 nanosheets increased with decreasing layer number .