Medical Application of Nano Tungsten Disulfide

Since Andre Geim and Konstantin Novoselov won the Nobel Prize in Physics for their research on graphene in 2010, graphene-like transition metal sulfides MS₂ (M=Mo, W, Nb, Ta) have attracted wide attention due to their unique physical and chemical properties.

Nano tungsten disulfide has unique lamellar structure, large specific surface area and remarkable electronic properties. It has a wide application space in catalysts, field-effect transistors and lithium-ion batteries. Tungsten disulfide has a hexagonal structure similar to graphene. The layer and layer are connected by weak van der Waals force, and can be stripped by simple liquid phase stripping method and ultrasound-assisted stripping. Stable monolayer or few layers of tungsten disulfide dispersions were prepared by ionization or lithium ion intercalation stripping, which laid an important foundation for the application of tungsten disulfide nanosheets in biomedical field.

Teo et al. used WST-8 and MTT methods to study the toxicity of tungsten disulfide nanotablets on human alveolar epithelial cells (A549). The results showed that A549 cells maintained a survival rate of more than 80% after incubation for 24 hours at a maximum concentration of 400 ug/mL. It was confirmed that monolayer tungsten disulfide still exhibited low cytotoxicity to A549 cells at high concentration. Importantly, nano-tungsten disulfide has a large specific surface area, combined with good dispersion in aqueous solution and low cytotoxicity, it has a good medical application prospect in high-efficiency drug carriers.

The advantages of high efficiency and low toxicity of nano-tungsten disulfide can also be demonstrated by another example. In the Advanced Materials journal, a leading international journal in Materials Science in 2014, a team led by Professor Liu Zhuang, Institute of Functional Nano-materials and Soft Substances, Suzhou University, also confirmed this view. Scientists have successfully developed photothermal treatment of nano-tungsten disulfide tablets. The reagent was successfully applied to the optical treatment of tumors.

It has been reported that nano tungsten disulfide nanosheets with uniform size were obtained by lithium ion intercalation, and then polyethylene glycol polymer was modified on the surface of the nanosheets to make them more water-soluble and biocompatible, and tungsten disulfide nanomaterials have good optical absorption properties in the near infrared region. Sulfide nanotablets were injected into mice via tail vein and enriched in the tumor site through the high permeability and retention effect (EPR effect). Because tungsten can absorb X-rays, it is the first time that good CT imaging of tumors has been achieved in animal models. At the same time, based on the near infrared absorption properties of tungsten sulfide nanomaterials, it can also be used for photoacoustic imaging of tumors. And under the irradiation of near infrared laser, all tumors were completely destroyed to achieve the goal of complete cure. Systematic toxicity studies showed that no obvious toxicity was observed in the injection dose, suggesting that tungsten disulfide transition may be widely used in clinical photothermal therapy of tumors.

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