Few-layered MoS2 nanocrystal, one of the typical two-dimensional (2D) transition metal dichalcogenide materials, show the unique mechanical, optical, electrical, and chemical properties correlated with their ultrathin atomic layer structure, tendering them an appealing alternative to fluorescent dyes, and have attracted particular attention in the scientific uses. MoS2 nanocrystals are flexible and operable for further modification, drug loading and controlled release because of the weak van der Waals interaction between its layers. It has been widely applied in medicine, drug delivery, diagnostics, and outstanding biocompatibility in living organisms.1–2
Cancer is one of the most significant hurdles that endanger human health, among which lung is the most general reason for cancer-related mortality. Chemotherapy is still one of the commonly practiced healing modalities for cancer therapy over the former decades. However, chemotherapy yields some remedial obstacles, such as harsh adverse effects, low solubility, and the trend to cause drugs resistance. However, the nanotechnology trade is rapidly advancing, and nanoparticles spot applicability in various areas of our real world applications. Hence, the possibility of the communication of individuals to different kinds of nanoparticles is also proceeding. For this purpose, it is essential to study how nanoparticles can influence human bodies, as they can get there by breath, dermal touch, or ingestion. Although nanocrystals have been produced and applied for a few decades, their impact on health and the environment has not been deeply studied due to the complicatedness of the interplays of nanocrystals and their ingredients with cells.
The challenges in producing synthesis and the versatility of nanocrystals compositions and a broad spectrum of available of surface ligands are still there. Several nanoparticles such as carbon nanotubes, graphene, fullerenes, or quantum dots, have been synthesized as they manifest the encouraging potential to defeat the shortcomings of chemotherapy medicines for cancer treatment. Correlated to specific nanoparticles, two-dimensional (2D) nanoparticles occupy unique chemical, optical, and electronic characteristics and are therefore granted unique curative tools for biomedicine, particularly cancer therapy. The bulk MoS2 contains multilayered arrangements with weak van der Waals forces between layers and strong S-Mo − S interlayer covalent bonding. The inadequate van der Waals forces let peeling of the layered bulk crystals to top-down prepare mono or few-layer MoS2. Hence, mechanical split, electrochemical intercalation, liquid-phase exfoliation, ultrasonic route, and hemolysis process have been investigated to produce mono or few-layer MoS2. These methods also lack low productivity, complicated process, time waste, and severe restrictions. In addition, control over MoS2 production through scalable route is needed to unravel its full potential. Thus, it is severe to produce new approaches to manufacture layer MoS2 with the necessary size to study the consequent emerging optoelectronics properties.
Some compelling reports demonstrate that 2D nanoparticle remedy's promising potential in the practical section and targeted control of cancer healings 27. More extra effort has been paid to search for other similar 2D materials relative to distinct unique properties. MoS2 nanoparticle, as a variety of transition metal dichalcogenides (TMDCs), illustrated potential applications for nanoelectronic, energy storage devices, and electrochemical storage, catalysis, and sensing applications. Notwithstanding the remarkable progress with MoS2 nanoparticle synthesis, it is necessary to produce a simplistic path for producing MoS2 nanocrystals with steady fluorescence. MoS2 is an excellent material having high dielectric constant, thin and large surface area that steadily increases the propagation path of light inside the sample. It also shows considerable formation of surface defects having Mo and S vacancies during synthesis process and acts as dipoles under the irradiation of light to boost interface polarization and defect dipole polarization for more attenuation of light. Over the past few years, the synthesis and use of atomically thin MoS2 nanocrystals have extensive research attention in material science. 3–5
Here, we show the synthesis and treatment of MoS2 nanocrystals for the viability of A549 cancer cells. This work intends to show an eco-friendly, facile, and reproducible synthesis method based on hydrothermal process for the scalable production of MoS2 nanocrystals (2–10 nm). This work explains preparing few-layer MoS2 nanocrystals with a small size pattern through a one-step hydrothermal method utilizing sodium molybdate and thioacetamide as sodium and sulfur source materials, respectively. Cost-effective and facile approaches for MoS2 nanocrystals controllable synthesis are quiet under essential demand, and the potential biomedical application of these MoS2 nanocrystals should be further investigated. Excitation-dependent PL spectra are observed, and the red shifting of emission spectra is mainly founded due to the size effect. As the study on TMDs, nanomaterials' toxicity is still in its origin with hardly a few assessments conducted on a mono or few-layer TMDs (e.g.MoS2, WS2), it is not unexpected that no conforming researches have been carried to discover the toxicity of TMDs yet. Still, with the entrance of research and potential standardization TMDs in the prospect, it is necessary to begin studying the toxicological consequences of this assembly of nanomaterials to notify the health risks they may pretend.
This article details a straightforward, low-cost approach that employs an aqueous hydrothermal method for synthesizing two-dimensional molybdenum disulfide (MoS2) nanocrystals and their potential applications to explore cytotoxicity, bioimaging, and cellular uptake of A549 cancer cells. The high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) results revealed that the sizes of the as-grown polydispersed MoS2 nanocrystals range between 2 and 5 nm; their corresponding thicknesses were verified to lie between 2 and 1 nm, a shred of clear evidence that a few-layer of MoS2 nanocrystals had been synthesized. Photoluminescence (PL) and time-resolved PL spectra for the MoS2 nanocrystals exhibited a strong emission in the blue region with a further slow decay constant.
Hence, in this report, the human lung carcinoma epithelial cell line (A549) after 24 h exposure to the MoS2 nanocrystals was estimated and interpreted by applying the methyl-thiazolyl diphenyl-tetrazolium bromide (MTT) and water-soluble trypan blue assays. A549 cell line was favorably preferred for this research because the lungs are expected to be the first place in which TMD occupies and communicates with the whole body when breathed into the respiratory tract. MTT and trypan blue assays are founded cell viability assays that act in the same way. The number of cells surviving viable after nursing with the MoS2 will be comparable to the formazan product's color intensity. By using both MTT and trypan blue assays in our research, we could be convinced that the cytotoxicity results are assured if the order collected from each assay were consistent and complemented each other. In this direction, we analyzed the sensitivity of A549 cells to the tested nanomaterials. We monitored cell viability with trypan blue and MTT assay tests. Reactive oxygen species (ROS) formation produced by MoS2 nanocrystals was also studied. Our research is also based on morphological studies with the usage of microscopic study. The MoS2 nanocrystals produced have excellent dispersal, small size, and PL features in aqueous suspension and encouraged biomedicine applications.6–8