Low Cytotoxicity and Genotoxicity of Two-Dimensional MoS2 and WS2

Anti-Inflammatory and Immunomodulatory Properties of Inorganic Fullerene-Like Tungsten Disulfide Nanoparticles in the Culture of Human Peripheral Blood Mononuclear Cells

Tungsten disulfide (WS2) nanoparticles have emerged in the biomedical field as potential theranostic agents due to their unique properties, including biocompatibility. However, their impact on the immune response remains unexplored. This study aimed to evaluate the effects of inorganic fullerene-like WS2 (IF-WS2) nanostructures on human peripheral blood mononuclear cells (PBMCs) in vitro. The study investigated several parameters to evaluate the effects of IF-WS2 nanoparticles. Cytotoxicity was assessed by measuring cell viability, apoptosis, and necrosis. Internalization of IF-WS2 by PBMCs was analyzed using morphological and flow cytometric techniques. Proliferation was studied in CellTrace Far Red-prestained total PBMCs stimulated with phytohemagglutinin (PHA) and in isolated T cell cultures stimulated with CD3/CD28-coated beads. Additionally, the production of cytokines and chemokines was measured in culture supernatants of total PBMCs and T cells. IF-WS2 nanoparticles were non-cytotoxic up to a concentration of 200 µg/mL. Concentrations ≥25 µg/mL inhibited PHA-stimulated PBMC proliferation but did not affect T cell proliferation. Morphological and flow cytometric analysis demonstrated dose- and time-dependent internalization of IF-WS2 by macrophages. Additionally, IF-WS2 significantly reduced the production of pro-inflammatory cytokines (IL-1β, TNF-α, IL-8, MCP-1, and GRO-α) in PHA-stimulated PBMCs. Th1, Th17, and Th21 cytokines were downregulated, while Th2, Th9, and T regulatory cytokines were upregulated. In conclusion, this study demonstrated for the first time that pristine IF-WS2 nanoparticles, at non-cytotoxic concentrations, exhibit notable anti-inflammatory and immunomodulatory properties on activated PBMCs in vitro.

Near-Infrared Light-Responsive Molybdenum Disulfide Nanosheets for Controlling the Release of Nimodipine as NIR-Drug Delivery System

Here, we present a photothermally triggered drug delivery nanosystem MoS2-NIMO-CHIT-SH, using the thiolated chitosan (CHIT-SH)-modified molybdenum disulfide (MoS2) nanosheets as near-infrared (NIR) photo-responsive carriers, loaded with the dihydropyridine calcium antagonist drug Nimodipine (NIMO). Although NIMO is used to treat stroke, migraine, Alzheimer's disease, cerebrovascular spasms, and hypertension, this drug is poorly water-soluble, with low bioavailability and lack of selectivity. Thus, there is an urgent need for a novel approach to creating NIMO formulations that are safe, effective, and have better solubility and bioavailability. To overcome these problems, we develop a cationic biopolymer functionalized MoS2 nanosheets as a photothermal drug carrier system to facilitate the NIR light-induced release of NIMO drugs. MoS2 nanosheets (<150 nm) as NIMO drug carriers are prepared through simple exfoliation of their bulk phase and then functionalized with CHIT-SH biopolymer to increase their physiological stability and biocompatibility. According to the results, MoS2-NIMO-CHIT-SH nanocomposites show strong NIR absorbance, which makes them a promising candidate for photothermal therapy.

Persistent Photoinduced Antibacterial Activity of MoS2 Nanosheets Immobilized in Porous Polymer Beads

Reactive oxygen species (ROS) photogenerated by two-dimensional (2D) nanomaterials provide a means of delivering persistent antibacterial activity in fluid media. Semiconducting molybdenum disulfide (MoS2) nanosheets are an attractive option for exploiting such activity by using visible light. However, the tendency of MoS2 nanosheets in suspension to restack or otherwise aggregate remains a critical obstacle, as it results in the loss of the desired photoactivity. We report here the development of persistent antibacterial activity by successfully immobilizing MoS2 nanosheets within porous cross-linked polymer beads. The nanosheet-loaded beads demonstrate continuous antibacterial activity against model species under visible-light exposure. The bactericidal activity is associated with ROS-mediated oxidative organismal stress, as assessed through chemical methods using fluorescent probes and gene-level biological studies. The porous beads demonstrate an effective antifouling capability and were physically stable with sustained bactericidal activity at an average of 99% over 5 cycles. The ability to confer reusable, continuous antibacterial activity under visible-light illumination is attractive in the context of the development of sustainable solutions for photoinduced antibacterial materials.

Elucidation of Potential Genotoxicity of MXenes Using a DNA Comet Assay

MXenes are among the most diverse and prominent 2D materials. They are being explored in almost every field of science and technology, including biomedicine. In particular, they are being investigated for photothermal therapy, drug delivery, medical imaging, biosensing, tissue engineering, blood dialysis, and antibacterial coatings. Despite their proven biocompatibility and low cytotoxicity, their genotoxicity has not been addressed. To investigate whether MXenes interfere with DNA integrity in cultured cells, we loaded the cells with MXenes and examined the fragmentation of their chromosomal DNA by a DNA comet assay. The presence of both Ti3C2Tx and Nb4C3Tx MXenes generated DNA comets, suggesting a strong genotoxic effect in murine melanoma and human fibroblast cells. However, no corresponding cytotoxicity was observed, confirming that MXenes were well tolerated by the cells. The lateral size of the MXene flakes was critical for developing the DNA comets; submicrometer flakes induced the DNA comets, while larger flakes did not. MXenes did not induce DNA comets in dead cells. Moreover, the extraction of the chromosomal DNA from the MXene-loaded cells or mixing the purified DNA with MXenes showed no signs of DNA fragmentation. Unconstrained living MXene-loaded cells did not show cleavage of the DNA with MXenes under electrophoresis conditions. Thus, the DNA comet assay showed the ability of submicrometer MXene particles to penetrate living cells and induce DNA fragmentation under the applied field. The most probable mechanism of DNA comet formation is the rotation and movement of submicrometer MXene flakes inside cells in an electric field, leading to cleavage and DNA shredding by MXene's razor-sharp edges. Under all other conditions of interest, titanium- and niobium-carbide-based MXenes showed excellent biocompatibility and no signs of cytotoxicity or genotoxicity. These findings may contribute to the development of strategies for cancer therapy.

Recent advances in two-dimensional materials for drug delivery

Two-dimensional (2D) materials exhibit significant potential in biomedical applications, particularly as drug carriers. Thus, 2D materials, including graphene, black phosphorus, transition metal dichalcogenides, transition metal carbides/nitrides, and hexagonal boron nitride, have been extensively studied. Their large specific surface area, abundant surface active sites, and excellent biocompatibility and biodegradability make them ideal platforms for drug loading and delivery. By optimizing the physicochemical properties and methods for the surface modification of 2D materials, improved drug release mechanisms and enhanced combination therapy effects can be achieved, providing a reliable foundation for efficient cancer treatment. This review provides a comprehensive analysis of the recent advances in the utilization of 2D materials for drug delivery. It systematically categorizes and summarizes the preparation methodologies, surface modification strategies, application domains, primary advantages and potential drawbacks of various 2D materials in the biomedical field. Furthermore, it provides an extensive overview of current challenges in this field and outlines potential future research directions for 2D materials in drug delivery based on existing issues.

2D Materials for Potable Water Application: Basic Nanoarchitectonics and Recent Progresses

Water polluted by toxic chemicals due to waste from chemical/pharmaceuticals and harmful microbes such as E. Coli bacteria causes several fatal diseases; and therefore, water filtration is crucial for accessing clean and safe water necessary for good health. Conventional water filtration technologies include activated carbon filters, reverse osmosis, and ultrafiltration. However, they face several challenges, including high energy consumption, fouling, limited selectivity, inefficiencies in removing certain contaminants, dimensional control of pores, and structural/chemical changes at higher thermal conditions and upon prolonged usage of water filter. Recently, the advent of 2D materials such as graphene, BN, MoS2, MXenes, and so on opens new avenues for advanced water filtration systems. This review delves into the nanoarchitectonics of 2D materials for water filtration applications. The current state of water filtration technologies is explored, the inherent challenges they face are outlines, and the unique properties and advantages of 2D materials are highlighted. Furthermore, the scope of this review is discussed, which encompasses the synthesis, characterization, and application of various 2D materials in water filtration, providing insights into future research directions and potential industrial applications.

Notable synthesis, properties and chemical gas sensing trends on molybdenum disulphides and diselenides two-dimensional nanostructures: A critical review

Evaluation of synthesis methods, notable properties, and chemical gas sensing properties of molybdenum disulphides and diselenides two-dimensional nanosheets is unfold. This is motivated by the fact that the two dichalcogenides have good sensitivity and selectivity to different harmful gases at ambient temperatures. Synthesis methods explored include exceptional top-down and bottom-up approaches, which consider physical and chemical compositional inceptions. Mechanical exfoliation in both molybdenum disulphides and diselenides nanosheets demonstrate good crystalline purity with structural alterations under varying stacking conditions. These chalcogenides exhibit low energy band gaps of ±1.80 eV for MoS2 and ±1.60 eV for MoSe2, which reduces with introduction of impurities. Thus, upon doping with other metal elements, a transformation from either n-type or p-type semiconductors is normally observed, leading to tuneable electronic properties. Thus, different gases such as methane, ethanol, toluene, ammonia, nitrogen oxide have been systematically detected using molybdenum disulphide and diselenide based thin films as sensing platforms. This review highlights structural, electronic and morphological characteristics of the two dichalcogenides which influences the sensitivity and selectivity ability for a couple of gases at ambient temperatures. The strategies for enhancing the selectivity by introducing defects, impurities and interfacing with other composites expanding the choice of these gases wider is also discussed in details. The review also provides overviews of challenges and limitations that open new research avenues to further enriching both chalcogenides as flexible, stable and cost effective state-of-the-art chemical gas sensors.

Polydiolcitrate-MoS2 Composite for 3D Printing Radio-Opaque, Bioresorbable Vascular Scaffolds

Implantable polymeric biodegradable devices, such as biodegradable vascular scaffolds, cannot be fully visualized using standard X-ray-based techniques, compromising their performance due to malposition after deployment. To address this challenge, we describe a new radiopaque and photocurable liquid polymer-ceramic composite (mPDC-MoS2) consisting of methacrylated poly(1,12 dodecamethylene citrate) (mPDC) and molybdenum disulfide (MoS2) nanosheets. The composite was used as an ink with microcontinuous liquid interface production (μCLIP) to fabricate bioresorbable vascular scaffolds (BVS). Prints exhibited excellent crimping and expansion mechanics without strut failures and, importantly, with X-ray visibility in air and muscle tissue. Notably, MoS2 nanosheets displayed physical degradation over time in phosphate-buffered saline solution, suggesting the potential for producing radiopaque, fully bioresorbable devices. mPDC-MoS2 is a promising bioresorbable X-ray-visible composite material suitable for 3D printing medical devices, such as vascular scaffolds, that require noninvasive X-ray-based monitoring techniques for implantation and evaluation. This innovative biomaterial composite system holds significant promise for the development of biocompatible, fluoroscopically visible medical implants, potentially enhancing patient outcomes and reducing medical complications.

First-principles calculations on monolayer WX2 (X = S, Se) as an effective drug delivery carrier for anti-tuberculosis drugs

Tuberculosis (TB) remains a major global health concern, necessitating the exploration of novel drug delivery systems to combat the challenges posed by conventional approaches. We investigated the potential of monolayer transition metal dichalcogenides (TMDs) as an innovative platform for efficient and targeted delivery of antituberculosis drugs. Specifically, the electronic and optical properties of prominent TB drugs, isoniazid (INH) and pyrazinamide (PZA), adsorbed on tungsten diselenide (WSe2) and tungsten disulfide (WS2) monolayers were studied using first-principles calculations based on density functional theory (DFT). The investigation revealed that the band gaps of WSe2 and WS2 monolayers remain unaltered upon adsorption of PZA or INH, with negative adsorption energy indicating stable physisorption. We explored different vertical and horizontal configurations, and the horizontal ones were more stable. When INH and PZA drugs were horizontally adsorbed together on WSe2, the most stable configuration was found with an adsorption energy of -2.35 eV. Moreover, the adsorbed drugs could be readily released by light within the visible or near-infrared (NIR) wavelength range. This opened up possibilities for their potential application in photothermal therapy, harnessing the unique properties of these 2D materials. The comprehensive analysis of the band structures and density of states provides valuable insights into how the drug molecules contributed to the conduction and valence bands. The optical responses of anti-TB drugs adsorbed in 2D WSe2 and WS2 were similar to those of pristine 2D WSe2 and WS2. We demonstrated the temperature-dependent release mechanism of our 2D WSe2 and WS2 drug complexes, confirming the feasibility of releasing the discussed anti-tuberculosis drugs by generating heat through photothermal therapy. These findings hold significant promise for developing innovative drug delivery systems that have enhanced efficacy for targeted and low-toxic TB treatment.

Recent Advances in Two-Dimensional Nanomaterials for Healthcare Monitoring

The development of advanced technologies for the fabrication of functional nanomaterials, nanostructures, and devices has facilitated the development of biosensors for analyses. Two-dimensional (2D) nanomaterials, with unique hierarchical structures, a high surface area, and the ability to be functionalized for target detection at the surface, exhibit high potential for biosensing applications. The electronic properties, mechanical flexibility, and optical, electrochemical, and physical properties of 2D nanomaterials can be easily modulated, enabling the construction of biosensing platforms for the detection of various analytes with targeted recognition, sensitivity, and selectivity. This review provides an overview of the recent advances in 2D nanomaterials and nanostructures used for biosensor and wearable-sensor development for healthcare and health-monitoring applications. Finally, the advantages of 2D-nanomaterial-based devices and several challenges in their optimal operation have been discussed to facilitate the development of smart high-performance biosensors in the future.

Unleashing the potential of tungsten disulfide: Current trends in biosensing and nanomedicine applications

The discovery of graphene ignites a great deal of interest in the research and advancement of two-dimensional (2D) layered materials. Within it, semiconducting transition metal dichalcogenides (TMDCs) are highly regarded due to their exceptional electrical and optoelectronic properties. Tungsten disulfide (WS2) is a TMDC with intriguing properties, such as biocompatibility, tunable bandgap, and outstanding photoelectric characteristics. These features make it a potential candidate for chemical sensing, biosensing, and tumor therapy. Despite the numerous reviews on the synthesis and application of TMDCs in the biomedical field, no comprehensive study still summarizes and unifies the research trends of WS2 from synthesis to biomedical applications. Therefore, this review aims to present a complete and thorough analysis of the current research trends in WS2 across several biomedical domains, including biosensing and nanomedicine, covering antibacterial applications, tissue engineering, drug delivery, and anticancer treatments. Finally, this review also discusses the potential opportunities and obstacles associated with WS2 to deliver a new outlook for advancing its progress in biomedical research.

Unveiling the antibacterial strategies and mechanisms of MoS2: a comprehensive analysis and future directions

Antibiotic resistance is a growing problem that requires alternative antibacterial agents. MoS2, a two-dimensional transition metal sulfide, has gained significant attention in recent years due to its exceptional photocatalytic performance, excellent infrared photothermal effect, and impressive antibacterial properties. This review presents a detailed analysis of the antibacterial strategies and mechanism of MoS2, starting with its morphology and synthesis methods and focusing on the different interaction stages between MoS2 and bacteria. The paper summarizes the main antibacterial mechanisms of MoS2, such as photocatalytic antibacterial, enzyme-like catalytic antibacterial, physical antibacterial, and photothermal-assisted antibacterial. It offers a comprehensive discussion focus on recent research studies of photocatalytic antibacterial mechanisms and categorizes them, guiding the application of MoS2 in the antibacterial field. Overall, the review provides an in-depth understanding of the antibacterial mechanisms of MoS2 and presents the challenges and future directions for the improvement of MoS2 in the field of high-efficiency antibacterial materials.

Recent progress in MoS2 nanostructures for biomedical applications: Experimental and computational approach

In the category of 2D materials, MoS2 a transition metal dichalcogenide, is a novel and intriguing class of materials with interesting physicochemical properties, explored in applications ranging from cutting-edge optoelectronic to the frontiers of biomedical and biotechnology. MoS2 nanostructures an alternative to heavy toxic metals exhibit biocompatibility, low toxicity and high stability, and high binding affinity to biomolecules. MoS2 nanostructures provide a lot of opportunities for the advancement of novel biosensing, nanodrug delivery system, electrochemical detection, bioimaging, and photothermal therapy. Much efforts have been made in recent years to improve their physiochemical properties by developing a better synthesis approach, surface functionalization, and biocompatibility for their safe use in the advancement of biomedical applications. The understanding of parameters involved during the development of nanostructures for their safe utilization in biomedical applications has been discussed. Computational studies are included in this article to understand better the properties of MoS2 and the mechanism involved in their interaction with biomolecules. As a result, we anticipate that this combined experimental and computational studies of MoS2 will inspire the development of nanostructures with smart drug delivery systems, and add value to the understanding of two-dimensional smart nano-carriers.

Distribution of molybdenum in soft tissues and blood of rats after intratracheal instillation of molybdenum(IV) sulfide nano- and microparticles

There is still little literature data on the toxicity and safety of the commonly used molybdenum (Mo) disulfide which is present in the working as well as living environments. Thus, an experiment was carried out involving rats, with single and repeated intratracheal exposure (in the latter case, 7 administrations at 2-week intervals with the analysis performed after 90 days) to lower (1.5 mg Mo kg-1 b.w.) and higher (5 mg Mo kg-1 b.w.) doses of molybdenum(IV) sulfide nanoparticles (MoS2-NPs) and microparticles (MoS2-MPs). The analysis of Mo concentrations in the tail and heart blood as well as in soft tissues (lung, liver, spleen, brain), after mineralization and bioimaging, was meant to facilitate an assessment of its accumulation and potential effects on the body following short- and long-term exposure. The multi-compartment model with an exponential curve of Mo concentration over time with different half-lives for the distribution and elimination phases of MoS2-MPs and MoS2-NPs was observed. After 24 h of exposure, a slight increase in Mo concentration in blood was observed. Next, Mo concentration indicated a decrease in blood concentration from 24 h to day 14 (the Mo concentration before the second administration), below the pre-exposure concentration. The next phase was linear, less abrupt and practically flat, but with an increasing trend towards the end of the experiment. Significantly higher Mo concentrations in MoS2-NPs and MoS2-MPs was found in the lungs of repeatedly exposed rats compared to those exposed to a single dose. The analysis of Mo content in the liver and the spleen tissue showed a slightly higher concentration for MoS2-NPs compared to MoS2-MPs. The results for the brain were below the calculated detection limit. Results were consistent with results obtained by bioimaging technique.

Perturbation of autophagy pathways in murine alveolar macrophage by 2D TMDCs is chalcogen-dependent

Increasing risks of incidental and occupational exposures to two-dimensional transition metal dichalcogenides (2D TMDCs) due to their broad application in various areas raised their public health concerns. While the composition-dependent cytotoxicity of 2D TMDCs has been well-recognized, how the outer chalcogenide atoms and inner transition metal atoms differentially contribute to their perturbation on cell homeostasis at non-lethal doses remains to be identified. In the present work, we compared the autophagy induction and related mechanisms in response to WS2, NbS2, WSe2 and NbSe2 nanosheets exposures in MH-S murine alveolar macrophages. All these 2D TMDCs had comparable physicochemical properties, overall cytotoxicity and capability in triggering autophagy in MH-S cells, but showed outer chalcogen-dependent subcellular localization and activation of autophagy pathways. Specifically, WS2 and NbS2 nanosheets adhered on the cell surface and internalized in the lysosomes, and triggered mTOR-dependent activation of autophagy. Meanwhile, WSe2 and NbSe2 nanosheets had extensive distribution in cytoplasm of MH-S cells and induced autophagy in an mTOR-independent manner. Furthermore, the 2D TMDCs-induced perturbation on autophagy aggravated the cytotoxicity of respirable benzo[a]pyrene. These findings provide a deeper insight into the potential health risk of environmental 2D TMDCs from the perspective of homeostasis perturbation.

Enhanced mechanical properties and biocompatibility of bacterial cellulose composite films with inclusion of 2D MoS2 and helical carbon nanotubes for use as antimicrobial drug carriers

Bacterial cellulose (BC) is a biomaterial being investigated for a range of applications. Herein, BC films derived from nata de coco pieces are reinforced by two-dimensional molybdenum disulfide (MoS2) and helical carbon nanotubes (HCNTs) to enhance their tensile mechanical properties, and the biocompatibility of the BC composite films is demonstrated. A simple preparation is presented using a kitchen blender to disperse and blend the BC fibers and additives in a common fabrication medium, followed by vacuum filtration. The mechanical properties of the BC/MoS2/HCNTs composite films are enhanced due to the synergistic effect of MoS2 and HCNTs embedded in the BC films. The MoS2/HCNTs binary additive (1 phr) is capable of increasing the strength and Young's modulus by 148 % and 333 %, respectively, relative to the BC films. The cell cytotoxicity of the BC/MoS2/HCNTs films was assessed using an MTT assay. The composite films are biocompatible with a cell viability of L929 fibroblast cells >70 %, coupled with observations of direct cell attachment on the films. The composite films also exhibited good performance in absorbing and releasing gentamicin antibiotics to inhibit the growth of Escherichia coli and Staphylococcus aureus. The BC/MoS2/HCNTs films are thus potential BC-based candidates as biocompatible robust antibiotic carriers.

Casein-assisted exfoliation of tungsten disulfide nanosheets for biomedical applications

Our regular life can be more challenging by bone abnormalities. Bone tissue engineering is used for repairing, regenerating, or replacing bone tissue that has been injured or infected. It is effective in overcoming the drawbacks of conventional bone grafting methods like autograft and allograft by enhancing the effectiveness of bone regeneration. Recent discoveries have shown that the exfoliation of transition metal dichalcogenides (TMDs) with protein is in great demand for bone tissue engineering applications. WS2 nanosheets were developed using casein and subsequently characterized with different analytical techniques. Strong absorption peaks were observed in the UV-visible spectra at 520 nm and 630 nm. Alginate and alginate-casein WS2 microspheres were developed. Stereomicroscopic images of the microspheres are spherical in shape and have an average diameter of around 0.8 ± 0.2 mm. The alginate-casein WS2 microspheres show higher content of water absorption and retention properties than only alginate-containing microspheres. The apatite formation in the simulated bodily fluid solution was facilitated more effectively by the alginate-casein-WS2 microspheres. Additionally, alginate-casein-WS2 microspheres have a compressive strength is 58.01 ± 4 MPa. Finally, in vitro cell interaction studies reveals that both the microspheres are biocompatible with the C3H10T1/2 cells, and alginate-casein-WS2-based microspheres promote cell growth more significantly. Alginate-casein-WS2 microspheres promote alkaline phosphatase activity, and mineralization process. Additionally, alginate-casein-WS2-based microspheres exponentially enhance the genes for ALP, BMP-2, OCN, and Collage type-1. The produced alginate-casein-WS2 microspheres could be a suitable synthetic graft for a bone transplant replacement.

Single bacteria identification with second-harmonic generation in MoS2

Transition-metal dichalcogenides exhibit extraordinary optical nonlinearities, making them promising candidates for advanced photonic applications. Here, we present the microbial control over second-harmonic generation (SHG) in monolayer MoS2 and the identification of single-cell bacteria. Bacteria deposited on monolayer MoS2 induce a change in the SHG signal, in the form of anisotropic polarization responses that depend on the relative orientation of the bacteria with respect to the MoS2 crystallographic direction. The anisotropic enhancement is consistent with the presence of a tensile stress along the lateral direction of bacteria axis; SHG imaging is highly effective in monitoring biomaterial strain as low as 0.1%. We also investigate the ultraviolet-induced removal of single bacteria, through the SHG imaging of MoS2. By monitoring the transient SHG signals, we determine the rupture times for bacteria, which varies noticeably for each species. This allows us to distinguish specific bacteria that share habitats; SHG imaging is useful for label free identification of pathogens at the single cell levels such as E. coli and L. casei. This label-free detection and identification of pathogens at the single-cell level can have a profound impact on the development of diagnostic tools for various applications.

Trends and prospects of 2-D tungsten disulphide (WS2) hybrid nanosystems for environmental and biomedical applications

Recently, 2D layered transition metal dichalcogenides (TMDCs) with their ultrathin sheet nanostructure and diversified electronic structure have drawn attention for various advanced applications to achieve high-performance parameters. Unique 2D TMDCs mainly comprise transition metal and chalcogen element where chalcogen element layers sandwich the transition metal element layer. In such a case, various properties can be enhanced and controlled depending on the targeted application. Among manipulative 2D TMDCs, tungsten disulphide (WS2) is one of the emerging nano-system due to its fascinating properties in terms of direct band gap, higher mobility, strong photoluminescence, good thermal stability, and strong magnetic field interaction. The advancement in characterization techniques, especially scattering techniques, can help in study of opto-electronic properties of 2D TMDCs along with determination of layer variations and investigation of defect. In this review, the fabrication and applications are well summarized to optimize an appropriate WS2-TMDCs assembly according to focused field of research. Here, the scientific investigations on 2D WS2 are studied in terms of its structure, role of scattering techniques to study its properties, and synthesis routes followed by its potential applications for environmental remediation (e.g., photocatalytic degradation of pollutants, gas sensing, and wastewater treatment) and biomedical domain (e.g., drug delivery, photothermal therapy, biomedical imaging, and biosensing). Further, a special emphasis is given to the significance of 2D WS2 as a substrate for surface-enhanced Raman scattering (SERS). The discussion is further extended to commercial and industrial aspects, keeping in view major research gaps in existing research studies.

Ecotoxicological assessment of water phase exfoliated two-dimensional Group-VI transition metal dichalcogenides using zebrafish embryo model

Among emerging layered materials, 2D transition metal dichalcogenides (TMDs) nanosheets (n-sheets) have received increasing attention for optoelectronics, energy storage, and, recently, for bioremediation and advanced biomedical applications; however, a lack of ecotoxicological in vivo studies is evident. Herein, for the first time, the potential nanotoxicity of liquid phase exfoliated Group VI TMDs n-sheets (MoS2, WS2, WSe2, and MoSe2) was comparatively investigated using zebrafish embryos (Z-EBs) as an in-vivo model. The 2D n-sheets were produced directly in aqueous-medium, the obtained n-sheets were characterized by scanning electron microscopy, Raman and visible spectroscopy, and their potential nanotoxicity was investigated by fish embryo test OECD TG 236. Chorionated and dechorionated embryos were used to assess the severity of TMD exposure. The survival rate, sublethal alteration during embryogenesis, hatching rate, and mortality were evaluated. TMDs n-sheets tend to adhere to the Z-EBs surface depending on their chemistry. Despite this, TMDs did not show lethal effects; weak sublethal effects were found for MoS2 and WSe2, while slight hatching delays were registered for MoSe2 and WSe2. The observed effects are attributable to the TMDs' tendency to interact with Z-EBs, because of the different chemistry. This work demonstrates how water-dispersed TMDs are potential eco/biocompatible materials.

A polydiolcitrate-MoS2 composite for 3D printing Radio-opaque, Bioresorbable Vascular Scaffolds

Implantable polymeric biodegradable devices, such as biodegradable vascular stents or scaffolds, cannot be fully visualized using standard X-ray-based techniques, compromising their performance due to malposition after deployment. To address this challenge, we describe composites of methacrylated poly(1,12 dodecamethylene citrate) (mPDC) and MoS2 nanosheets to fabricate novel X-ray visible radiopaque and photocurable liquid polymer-ceramic composite (mPDC-MoS2). The composite was used as an ink with micro continuous liquid interface production (μCLIP) to fabricate bioresorbable vascular scaffolds (BVS). Prints exhibited excellent crimping and expansion mechanics without strut failures and, importantly, required X-ray visibility in air and muscle tissue. Notably, MoS2 nanosheets displayed physical degradation over time in a PBS environment, indicating the potential for producing bioresorbable devices. mPDC-MoS2 is a promising bioresorbable X-ray-visible composite material suitable for 3D printing medical devices, particularly vascular scaffolds or stents, that require non-invasive X-ray-based monitoring techniques for implantation and evaluation. This innovative composite system holds significant promise for the development of biocompatible and highly visible medical implants, potentially enhancing patient outcomes and reducing medical complications.

Fast detection of Staphylococcus aureus using thiol-functionalized WS2 quantum dots and Bi2O2Se nanosheets hybrid through a fluorescence recovery mechanism

Ultrafast and sensitive detection of Staphylococcus aureus (S. aureus), a harmful Gram-positive human pathogenic bacterium, by two-dimensional layered materials continues to be a challenge. Herein, we have studied the sensing of S. aureus using a tungsten disulfide (WS2) quantum dot (QD) and bismuth oxyselenide (Bi2O2Se) nanosheet (NS) hybrid through their unique optical functionalities. The WS2 QDs of a mean diameter of 2.5 nm were synthesized by liquid exfoliation. Due to the quantum confinement and functional groups, the WS2 QDs exhibit high fluorescence (FL) yield under UV excitation. The addition of Bi2O2Se NSs resulted in the adsorption of WS2 QDs on their surface, resulting in quenching of the FL emission due to nonfluorescent complex formation between the WS2 QDs and Bi2O2Se NSs. A specific sequencing single-standard DNA (ssDNA) aptamer, which identifies and explicitly binds with S. aureus, was attached to the defect sites of the WS2 QDs for selective detection. The thiol-modified ssDNA aptamers attach covalently to the WS2 QD defect sites, which was confirmed by Raman and X-ray photoelectron spectroscopy (XPS). The interaction of S. aureus with the aptamer functionalized WS2 QDs weakens the van der Waals interaction between the WS2 QDs and Bi2O2Se NSs, which results in the detachment of the WS2 QDs from the Bi2O2Se NS surface and restores the FL intensity of the WS2 QDs, thus allowing the efficient detection of S. aureus. Similar measurements with non-targeted bacteria show that the system is quite selective towards S. aureus. Our FL-based biosensor has a linear response in the range of 103-107 CFU mL-1 (colony formation unit mL-1) with a detection limit of 580 CFU mL-1. We have observed a fast response time of 15 minutes for sensing, which is superior to the previous reports. The proposed system was tested in human urine and can detect S. aureus in human urine samples selectively, proving its potential in real-life applications. The reported approach is versatile enough for sensing other biomolecules and metal ions by choosing suitable receptors.

Sludge biodrying coupled with photocatalysis improves the degradation of extracellular polymeric substances

The efficiency of sludge dewatering is limited by extracellular polymeric substances (EPS) during biodrying. This study investigated the effect of photocatalysis-mediated EPS degradation on sludge dewatering performance during the sludge biodrying process. The photocatalysis of municipal sludge was first carried out to choose a cost-efficient catalyst. Then sludge biodrying tests were performed using TiO2-coated amendment (TCA) and uncoated amendment (TUCA) as the control. Municipal sludge photocatalysis results showed that using TiO2 could efficiently degrade carbohydrates and proteins in the EPS within 60 min. After 20-day biodrying, photocatalysis significantly promoted a reduction in the moisture content and EPS by 17.64% and 6.88%, respectively. The surface-enhanced Raman scattering (SERS) intensities of the C-C-O symmetric stretching vibration peak of D-lactose and the C-S stretching vibration peak of cysteine were significantly decreased by approximately 33.19% and 44.76%, respectively, indicating that photocatalysis indeed promoted the reduction of polysaccharides and cysteine in the EPS, especially after the thermophilic phase. The hydrophilic amino acid content decreased by 23.02%, verifying that photocatalysis could improve EPS hydrophobicity. Consequently, municipal sludge biodrying coupled with photocatalysis promotes sludge EPS degradation and enhances sludge dewaterability, improving the efficiency of sludge biodrying.

Shape complementarity processes for ultrashort-burst sensitive M13-PEG-WS2-powered MCF-7 cancer cell sensors

Biomarkers have the potential to be utilized in disease diagnosis, prediction and monitoring. The cancer cell type is a leading candidate for next-generation biomarkers. Although traditional digital biomolecular sensor (DBS) technology has shown to be effective in assessing cell-based interactions, low cell-population detection of cancer cell types is extremely challenging. Here, we controlled the electrical signature of a two-dimensional (2D) nanomaterial, tungsten disulfide (WS2), by utilizing a combination of the Phage-integrated Polymer and the Nanosheet (PPN), viz., the integration of the M13-conjugated polyethylene glycol (PEG) and the WS2, through shape-complementarity phenomena, and developed a sensor system, i.e., the Phage-based DBS (P-DBS), for the specific, rapid, sensitive detection of clinically-relevant MCF-7 cells. The P-DBS attains a detection limit of 12 cells per μL, as well as a contrast of 1.25 between the MCF-10A sample signal and the MCF-7 sample signal. A reading length of 200 μs was further achieved, along with a relative cell viability of ∼100% for both MCF-7 and MCF-10A cells and with the PNN. Atomistic simulations reveal the structural origin of the shape complementarity-facilitated decrease in the output impedance of the P-DBS. The combination of previously unreported exotic sensing materials and digital sensor design represents an approach to unlocking the ultra-sensitive detection of cancer cell types and provides a promising avenue for early cancer diagnosis, staging and monitoring.

Advances in Bioresorbable Materials and Electronics

Transient electronic systems represent an emerging class of technology that is defined by an ability to fully or partially dissolve, disintegrate, or otherwise disappear at controlled rates or triggered times through engineered chemical or physical processes after a required period of operation. This review highlights recent advances in materials chemistry that serve as the foundations for a subclass of transient electronics, bioresorbable electronics, that is characterized by an ability to resorb (or, equivalently, to absorb) in a biological environment. The primary use cases are in systems designed to insert into the human body, to provide sensing and/or therapeutic functions for timeframes aligned with natural biological processes. Mechanisms of bioresorption then harmlessly eliminate the devices, and their associated load on and risk to the patient, without the need of secondary removal surgeries. The core content focuses on the chemistry of the enabling electronic materials, spanning organic and inorganic compounds to hybrids and composites, along with their mechanisms of chemical reaction in biological environments. Following discussions highlight the use of these materials in bioresorbable electronic components, sensors, power supplies, and in integrated diagnostic and therapeutic systems formed using specialized methods for fabrication and assembly. A concluding section summarizes opportunities for future research.

The mechanical, optical, and thermal properties of graphene influencing its pre-clinical use in treating neurological diseases

Rapid progress in nanotechnology has advanced fundamental neuroscience and innovative treatment using combined diagnostic and therapeutic applications. The atomic scale tunability of nanomaterials, which can interact with biological systems, has attracted interest in emerging multidisciplinary fields. Graphene, a two-dimensional nanocarbon, has gained increasing attention in neuroscience due to its unique honeycomb structure and functional properties. Hydrophobic planar sheets of graphene can be effectively loaded with aromatic molecules to produce a defect-free and stable dispersion. The optical and thermal properties of graphene make it suitable for biosensing and bioimaging applications. In addition, graphene and its derivatives functionalized with tailored bioactive molecules can cross the blood-brain barrier for drug delivery, substantially improving their biological property. Therefore, graphene-based materials have promising potential for possible application in neuroscience. Herein, we aimed to summarize the important properties of graphene materials required for their application in neuroscience, the interaction between graphene-based materials and various cells in the central and peripheral nervous systems, and their potential clinical applications in recording electrodes, drug delivery, treatment, and as nerve scaffolds for neurological diseases. Finally, we offer insights into the prospects and limitations to aid graphene development in neuroscience research and nanotherapeutics that can be used clinically.

Three-dimension chitosan hydrogel loading melanin composite nanoparticles for wound healing by anti-bacteria, immune activation and macrophage autophagy promotion

Application of Combined photodynamic therapy (PDT) and photothermal therapy (PTT) has become one of the most promising strategy to replace antibiotics and avoid the epidemic of drug-resistant strains during wound healing. However, high amount of reactive oxygen species (ROS) and high temperature cause severe stress response to normal tissues, leading to potential risks of wound healing. Herein, a three-dimension chitosan hydrogel melanin-glycine-C60 nanoparticles (MGC NPs) were prepared to realized effective anti-bacterial activity, immune activation and macrophage autophagy promotion in three-dimensional wound space without triggering stress response. MGC NP is a composite polymer material composed of natural melanin polymer, oligopeptide and carbon-based material, which showed excellent biological safety. By regulating the peptide length between melanin and C60 and nanoparticle content, a high ROS/heat environment at the upper wound site and a low ROS/heat environment at the lower region adjacent to the wound tissue were established to obtain a three-dimension hydrogel with precise PDT and PTT efficiency in different regions. Highly effective PDT/PTT was used to kill microorganisms in upper region, thus providing a barrier to reduce microbial infection. Mild PDT/PTT in lower region promoted the polarization of M1 macrophage to M2 macrophage and activated autophagy of M2 macrophages, regulating the immune microenvironment and promoting wound repair. In conclusion, the novel three-dimensional PDT/PTT therapy based on natural macromolecules proposed in this study accelerates wound healing through dual pathways on the premise of avoiding wound stress response, which is of great significance for the development of clinical strategies for phototherapy.

Applications of Polyaniline-Based Molybdenum Disulfide Nanoparticles against Brain-Eating Amoebae

Primary amoebic meningoencephalitis and granulomatous amoebic encephalitis are distressing infections of the central nervous system caused by brain-eating amoebae, namely, Naegleria fowleri and Acanthamoeba spp., respectively, and present mortality rates of over 90%. No single drug has been approved for use against these infections, and current therapy is met with an array of obstacles including high toxicity and limited specificity. Thus, the development of alternative effective chemotherapeutic agents for the management of infections due to brain-eating amoebae is a crucial requirement to avert future mortalities. In this paper, we synthesized a conducting polymer-based nanocomposite entailing polyaniline (PANI) and molybdenum disulfide (MoS₂) and explored its anti-trophozoite and anti-cyst potentials against Acanthamoeba castellanii and Naegleria fowleri. The intracellular generation of reactive oxygen species (ROS) and ultrastructural appearances of amoeba were also evaluated with treatment. Throughout, treatment with the 1:2 and 1:5 ratios of PANI/MoS₂ at 100 μg/mL demonstrated significant anti-amoebic effects toward A. castellanii as well as N. fowleri, appraised to be ROS mediated and effectuate physical alterations to amoeba morphology. Further, cytocompatibility toward human keratinocyte skin cells (HaCaT) and primary human corneal epithelial cells (pHCEC) was noted. For the first time, polymer-based nanocomposites such as PANI/MoS₂ are reported in this study as appealing options in the drug discovery for brain-eating amoebae infections.

Resolution of MoS2 Nanosheets-Induced Pulmonary Inflammation Driven by Nanoscale Intracellular Transformation and Extracellular-Vesicle Shuttles

Pulmonary exposure to some engineered nanomaterials can cause chronic lesions as a result of unresolved inflammation. Among 2D nanomaterials and graphene, MoS₂ has received tremendous attention in optoelectronics and nanomedicine. Here an integrated approach is proposed to follow up the transformation of MoS₂ nanosheets at the nanoscale and assesss their impact on lung inflammation status over 1 month after a single inhalation in mice. Analysis of immune cells, alveolar macrophages, extracellular vesicles, and cytokine profiling in bronchoalveolar lavage fluid (BALF) shows that MoS₂ nanosheets induced initiation of lung inflammation. However, the inflammation is rapidly resolved despite the persistence of various biotransformed molybdenum-based nanostructures in the alveolar macrophages and the extracellular vesicles for up to 1 month. Using in situ liquid phase transmission electron microscopy experiments, the dynamics of MoS₂ nanosheets transformation triggered by reactive oxygen species could be evidenced. Three main transformation mechanisms are observed directly at the nanoscale level: 1) scrolling of the dispersed sheets leading to the formation of nanoscrolls and folded patches, 2) etching releasing soluble MoO₄ ^- , and 3) oxidation generating oxidized sheet fragments. Extracellular vesicles released in BALF are also identified as a potential shuttle of MoS₂ nanostructures and their degradation products and more importantly as mediators of inflammation resolution.

Photo-Antibacterial Activity of Two-Dimensional (2D)-Based Hybrid Materials: Effective Treatment Strategy for Controlling Bacterial Infection

Bacterial contamination in water bodies is a severe scourge that affects human health and causes mortality and morbidity. Researchers continue to develop next-generation materials for controlling bacterial infections from water. Photo-antibacterial activity continues to gain the interest of researchers due to its adequate, rapid, and antibiotic-free process. Photo-antibacterial materials do not have any side effects and have a minimal chance of developing bacterial resistance due to their rapid efficacy. Photocatalytic two-dimensional nanomaterials (2D-NMs) have great potential for the control of bacterial infection due to their exceptional properties, such as high surface area, tunable band gap, specific structure, and tunable surface functional groups. Moreover, the optical and electric properties of 2D-NMs might be tuned by creating heterojunctions or by the doping of metals/carbon/polymers, subsequently enhancing their photo-antibacterial ability. This review article focuses on the synthesis of 2D-NM-based hybrid materials, the effect of dopants in 2D-NMs, and their photo-antibacterial application. We also discuss how we could improve photo-antibacterials by using different strategies and the role of artificial intelligence (AI) in the photocatalyst and in the degradation of pollutants. Finally, we discuss was of improving the photo-antibacterial activity of 2D-NMs, the toxicity mechanism, and their challenges.

Emerging Trends and Recent Progress of MXene as a Promising 2D Material for Point of Care (POC) Diagnostics

Two-dimensional (2D) nanomaterials with chemical and structural diversity have piqued the interest of the scientific community due to their superior photonic, mechanical, electrical, magnetic, and catalytic capabilities that distinguish them from their bulk counterparts. Among these 2D materials, two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides with a general chemical formula of Mn+1XnTx (where n = 1-3), together known as MXenes, have gained tremendous popularity and demonstrated competitive performance in biosensing applications. In this review, we focus on the cutting-edge advances in MXene-related biomaterials, with a systematic summary on their design, synthesis, surface engineering approaches, unique properties, and biological properties. We particularly emphasize the property-activity-effect relationship of MXenes at the nano-bio interface. We also discuss the recent trends in the application of MXenes in accelerating the performance of conventional point of care (POC) devices towards more practical approaches as the next generation of POC tools. Finally, we explore in depth the existing problems, challenges, and potential for future improvement of MXene-based materials for POC testing, with the goal of facilitating their early realization of biological applications.

Pulmonary toxicity of molybdenum disulphide after inhalation in mice

Molybdenum disulphide (MoS₂) is a constituent of many products. To protect humans, it is important to know at what air concentrations it becomes toxic. For this, we tested MoS₂ particles by nose-only inhalation in mice. Exposures were set to 13, 50 and 150 mg MoS₂/m³ (=8, 30 and 90 mg Mo/m³), corresponding to Low, Mid and High exposure. The duration was 30 min/day, 5 days/week for 3 weeks. Molybdenum lung-deposition levels were estimated based on aerosol particle size distribution measurements, and empirically determined with inductively coupled plasma-mass spectrometry (ICP-MS). Toxicological endpoints were body weight gain, respiratory function, pulmonary inflammation, histopathology, and genotoxicity (comet assay). Acellular reactive oxygen species (ROS) production was also determined. The aerosolised MoS₂ powder had a mean aerodynamic diameter of 800 nm, and a specific surface area of 8.96 m²/g. Alveolar deposition of MoS₂ in lung was estimated at 7, 27 and 79 µg/mouse and measured as 35, 101 and 171 µg/mouse for Low, Mid and High exposure, respectively. Body weight gain was lower than in controls at Mid and High exposure. The tidal volume was decreased with Low and Mid exposure on day 15. Increased genotoxicity was seen in bronchoalveolar lavage (BAL) fluid cells at Mid and High exposures. ROS production was substantially lower than for carbon black nanoparticles used as bench-mark, when normalised by mass. Yet if ROS of MoS₂ was normalised by surface area, it was similar to that of carbon black, suggesting that a ROS contribution to the observed genotoxicity cannot be ruled out. In conclusion, effects on body weight gain and genotoxicity indicated that Low exposure (13 mg MoS₂/m³, corresponding to 0.8 mg/m³ for an 8-hour working day) was a No Observed Adverse Effect Concentration (NOAEC,) while effects on respiratory function suggested this level as a Lowest Observed Adverse Effect Concentration (LOAEC).

Tungsten-based Nanomaterials in the Biomedical Field: A Bibliometric Analysis of Research Progress and Prospects

Tungsten-based nanomaterials (TNMs) with diverse nanostructures and unique physicochemical properties have been widely applied in the biomedical field. Although various reviews have described the application of TNMs in specific biomedical fields, there are still no comprehensive studies that summarize and analyze research trends of the field as a whole. To identify and further promote the development of biomedical TNMs, a bibliometric analysis method is used to analyze all relevant literature on this topic. First, general bibliometric distributions of the dataset by year, country, institute, referenced source, and research hotspots are recognized. Next, a comprehensive review of the subjectively recognized research hotspots in various biomedical fields, including biological sensing, anticancer treatments, antibacterials, and toxicity evaluation, is provided. Finally, the prospects and challenges of TNMs are discussed to provide a new perspective for further promoting their development in biomedical research.

Effects of WS2 Nanosheets on N2-fixing Cyanobacteria: ROS overproduction, cell membrane damage, and cell metabolic reprogramming

The ecotoxicity of tungsten disulfide (WS₂) nanomaterials remains unclear so far. Here, the toxicity of WS₂ nanosheets on N₂-fixing cyanobacteria (Nostoc sphaeroides) was evaluated. Specifically, Nostoc were cultivated in media spiked with different concentrations of WS₂ nanosheets (0, 0.05, 0.1 and 0.5 mg/L) for 96 h. Relative to unexposed cells, WS₂ nanosheets at 0.5 mg/L significantly decreased cell density, content of total sugar and protein by 10.9 %, 0.43 %, and 6.1 %, respectively. Gas chromatography-mass spectrometry (GC-MS)-based metabolomics revealed that WS₂ nanosheets exposure altered the metabolite profile of Nostoc in a dose-dependent manner. Energy metabolism related pathways, including the Calvin-Benson-Bassham (CBB) cycle and tricarboxylic acid (TCA) cycle, were significantly inhibited. In addition, WS₂ nanosheets exposure resulted in downregulation (20-40 %) of S-containing amino acids (cystine, methionine, and cysteine) and sulfuric acid. Additionally, fatty acids and antioxidant-related compounds (formononetin, catechin, epigallocatechin, dehydroascorbic acid, and alpha-tocopherol) in Nostoc were drastically decreased by 4-50 % upon exposure to WS₂ nanosheets, which implies oxidative stress induced by the nanomaterials. Biochemical assays for reactive oxygen species (ROS) and malondialdehyde (MDA) confirmed that WS₂ nanosheets triggered ROS overproduction and induced lipid peroxidation. Taken together, WS₂ exposure perturbed carbon (C), nitrogen (N), and sulfate (S) metabolism of Nostoc, which may influence C, N, and S cycling, given the important roles of cyanobacteria in these processes. These results highlight the need for caution in the application and environmental release of WS₂ nanomaterials to prevent unintended environmental impacts due to their potential ecotoxicity.

3D Neural Network Composed of Neurospheroid and Bionanohybrid on Microelectrode Array to Realize the Spatial Input Signal Recognition in Neurospheroid

There have been several studies for demonstration of 2D neural network using living cells or organic/inorganic molecules, but to date, there is no report of development of a 3D neural network in vitro. Based on developed bionanohybrid composed of protein, DNA, molybdenum disulfide nanoparticles, and peptides for controlling electrophysiological states of living cells, here, the in vitro 3D neural network composed of the bionanohybrid, 3D neurospheroid and the microelectrode array (MEA) is developed. After production of the 3D neurospheroid derived from human neural stem cells, the bionanohybrid developed on the MEA successfully semi-penetrates the neurites of the 3D neurospheroid and forms the 3D neural network. The developed 3D neural network successfully exhibited the electrophysiological output signals of the 3D neurospheroid by transmitting the input signal applied by the bionanohybrid. Moreover, by using the selectively immobilized bionanohybrid on the MEA, the spatial input signal recognition in the neurospheroid of 3D neural network is realized for the first time. This newly developed in vitro 3D neural network provides a promising strategy to be applied in brain-on-a-chip, brain disease-related drug efficacy evaluation, bioelectronics, and bioelectronic medicine.

Toxicological effects of WS2 nanomaterials on rice plants and associated soil microbes

As an important member of transition-metal dichalcogenides family, tungsten disulfides nanomaterials (WS₂ NMs) have a wide range of applications. To date, their environmental risks remain largely unknown. In this study, rice plants were grown in soil amended with different concentrations (0, 10, and 100 mg/kg) of WS₂ NMs for 4 weeks. WS₂ NMs at 100 mg/kg significantly increased MDA (malondialdehyde) content and decreased total antioxidant capacities of leaves, indicating the oxidative response induced by WS₂ NMs. Meanwhile, WS₂ NMs at 100 mg/kg significantly decreased root biomass compared to control, indicating the negative impacts of WS₂ NMs on plant growth. While exposure to 100 mg/kg WS₂ NMs significantly increased soil bioavailable Cu, Fe, Zn, and Olsen-P, and increased the content of Cu, Fe, Zn, and P in rice leaves. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis showed that W was taken up by rice roots and translocated into leaves. The impact of WS₂ on soil microbial communities was evaluated by 16S rRNA gene sequencing. WS₂ NMs at 100 mg/kg significantly decreased soil microbial diversity, as indicated by decreased Shannon index. In addition, 100 mg/kg WS₂ shifted the soil microbial profile, the relative abundance of the phylum Acidobacteriota decreased, and Actinobacteriota increased. Taken together, the soil microbial community's diversity and composition have been altered upon exposure to 100 mg/kg WS₂ NMs. The results of this study provide some basic information regarding the environmental behavior and phytotoxicity of WS₂ NMs, which is valuable for safe use of WS₂ NMs.

Nano-bio interactions of 2D molybdenum disulfide

Two-dimensional (2D) molybdenum disulfide (MoS2) is an ultrathin nanomaterial with a high degree of anisotropy, surface-to-volume ratio, chemical functionality and mechanical strength. These properties together enable MoS2 to emerge as a potent nanomaterial for diverse biomedical applications including drug delivery, regenerative medicine, biosensing and bioelectronics. Thus, understanding the interactions of MoS2 with its biological interface becomes indispensable. These interactions, referred to as "nano-bio" interactions, play a key role in determining the biocompatibility and the pathways through which the nanomaterial influences molecular, cellular and biological function. Herein, we provide a critical overview of the nano-bio interactions of MoS2 and emphasize on how these interactions dictate its biomedical applications including intracellular trafficking, biodistribution and biodegradation. Also, a critical evaluation of the interactions of MoS2 with proteins and specific cell types such as immune cells and progenitor/stem cells is illustrated which governs the short-term and long-term compatibility of MoS2-based biomedical devices.

Recent Progress in Phase Regulation, Functionalization, and Biosensing Applications of Polyphase MoS2

The disulfide compounds of molybdenum (MoS₂ ) are layered van der Waals materials that exhibit a rich array of polymorphic structures. MoS₂ can be roughly divided into semiconductive phase and metallic phase according to the difference in electron filling state of the 4d orbital of Mo atom. The two phases show completely different properties, leading to their diverse applications in biosensors. But to some extent, they compensate for each other. This review first introduces the relationship between phase state and the chemical/physical structures and properties of MoS₂ . Furthermore, the synthetic methods are summarized and the preparation strategies for metastable phases are highlighted. In addition, examples of electronic and chemical property designs of MoS₂ by means of doping and surface modification are outlined. Finally, studies on biosensors based on MoS₂ in recent years are presented and classified, and the roles of MoS₂ with different phases are highlighted. This review offers references for the selection of materials to construct different types of biosensors based on MoS₂ , and provides inspiration for sensing performance enhancement.

Multifunctional Hybrid MoS2-PEGylated/Au Nanostructures with Potential Theranostic Applications in Biomedicine

In this work, flower-like molybdenum disulfide (MoS₂) microspheres were produced with polyethylene glycol (PEG) to form MoS₂-PEG. Likewise, gold nanoparticles (AuNPs) were added to form MoS₂-PEG/Au to investigate its potential application as a theranostic nanomaterial. These nanomaterials were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), photoelectron X-ray spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), cyclic voltammetry and impedance spectroscopy. The produced hierarchical MoS₂-PEG/Au microstructures showed an average diameter of 400 nm containing distributed gold nanoparticles, with great cellular viability on tumoral and non-tumoral cells. This aspect makes them with multifunctional characteristics with potential application for cancer diagnosis and therapy. Through the complete morphological and physicochemical characterization, it was possible to observe that both MoS₂-PEG and MoS₂-PEG/Au showed good chemical stability and demonstrated noninterference in the pattern of the cell nucleus, as well. Thus, our results suggest the possible application of these hybrid nanomaterials can be immensely explored for theranostic proposals in biomedicine.

MoS2 based nanomaterials: Advanced antibacterial agents for future

Bacterial infections are yet another serious threat to human health. Misuse or overuse of conventional antibiotics has led to the arrival of various super resistant bacteria along with many serious side effects to human body. In this exigent circumstance, the use of nanomaterial based antibacterial agents is one of the most appropriate solutions to fight against bacteria thereby causing an inhibition to bacterial proliferation. Recent studies show that, due to the large surface area, high biocompatibility, strong near-infrared (NIR) absorption and low cytotoxicity, molybdenum disulphide (MoS₂), an extraordinary member in the transition metal dichalcogenides (TMDs) is extensively explored in the obliteration of many drug resistant bacteria, photothermal therapy and drug delivery. MoS₂ based nanomaterials can effectively prevent bacterial growth through many mechanisms. Through this review, we have tried to provide an inclusive knowledge on the recent progress of antibacterial studies in MoS₂ based nanomaterials including MoS₂ nanosheets, nanoflowers, quantum dot (QD), hybrid nanocomposites and polymer nanocomposites. Moreover, toxicity of MoS₂ based nanomaterials is described at the end of the review.

Development of Biocompatible Polyhydroxyalkanoate/Chitosan-Tungsten Disulphide Nanocomposite for Antibacterial and Biological Applications

The unique structures and multifunctionalities of two-dimensional (2D) nanomaterials, such as graphene, have aroused increasing interest in the construction of novel scaffolds for biomedical applications due to their biocompatible and antimicrobial abilities. These two-dimensional materials possess certain common features, such as high surface areas, low cytotoxicities, and higher antimicrobial activities. Designing suitable nanocomposites could reasonably improve therapeutics and reduce their adverse effects, both medically and environmentally. In this study, we synthesized a biocompatible nanocomposite polyhydroxyalkanoate, chitosan, and tungsten disulfide (PHA/Ch-WS₂). The nanocomposite PHA/Ch-WS₂ was characterized by FESEM, elemental mapping, FTIR, and TGA. The objective of this work was to investigate the antimicrobial activity of PHA/Ch-WS₂ nanocomposites through the time–kill method against the multi-drug-resistant model organisms Escherichia coli (E. coli) K1 and methicillin-resistant Staphylococcus aureus (MRSA). Further, we aimed to evaluate the cytotoxicity of the PHA/Ch-WS₂ nanocomposite using HaCaT cell lines by using a lactate dehydrogenase (LDH) assay. The results demonstrated very significant bactericidal effects of the PHA/Ch-WS₂ nanocomposite, and thus, we hypothesize that the nanocomposite would feasibly suit biomedical and sanitizing applications without causing any adverse hazard to the environment.

Extracellular polymeric substances mediate defect generation and phytotoxicity of single-layer MoS2

Two-dimensional transition metal dichalcogenide (TMDC) nanomaterials have attracted tremendous research interest in various fields, but the effects of eco-corona formation on the transformation mechanisms and ecological risk of TMDCs remain largely unknown. The effect of eco-corona formation on TMDC reactivity was explored using extracellular polymeric substances (EPS) as the eco-corona constituents and single-layer molybdenum disulfide (SLMoS₂) as the model TMDC. We found that EPS promoted lattice distortion and the formation of defects (sulfur vacancies and pores) on SLMoS₂ after it was aged (precoated) with EPS under simulated visible-light irradiation. In addition, the EPS-corona induced higher free radical (especially hyperoxide radical) photogeneration by SLMoS₂. Furthermore, compared to pristine SLMoS₂, SLMoS₂-EPS exhibited stronger developmental inhibition, oxidative stress, membrane damage, photosynthetic toxicity and metabolic perturbation effects on Chlorella vulgaris. However, the endocytosis pathway (especially macropinocytosis) of SLMoS₂ entry into C. vulgaris was inhibited by EPS. Metabolic and transcriptomic analyses revealed that the enhanced toxicity of SLMoS₂-EPS was associated with the downregulation of fatty acid metabolism and transcription related to photosynthesis, respectively. The present work provides mechanistic insights into the roles of the EPS-corona on the environmental transformation and phytotoxicity of TMDCs, which benefit environmental safety assessments and sustainable applications of engineered nanomaterials.

Environmental implications of MoS2 nanosheets on rice and associated soil microbial communities

Molybdenum disulfide (MoS₂) is a transition metal dichalcogenides (TMDCs) material that is seeing rapidly increasing use. The wide range of applications will result in significant environmental release. Here, the impact of MoS₂ nanosheets on rice and associated soil microbial communities was evaluated. Rice plants were grown for 4 weeks in a natural paddy soil amended with either 1T or 2H phase MoS₂ nanosheets at 10 and 100 mg kg^-1. The 1T MoS₂ nanosheets have a significantly greater dissolution rate (58.9%) compared to 2H MoS₂ (4.4%), indicating the instability of 1T MoS₂ in environment. High dissolution rate resulted in a high Mo bioaccumulation in rice leaves (272 and 189 mg kg^-1 under 1T and 2H exposure at 100 mg kg^-1). However, this did not induce overt phytotoxicity, as indicated by a range of phenotypic or biochemical based determine endpoints, e.g., biomass, photosynthetic pigments, and malondialdehyde (MDA) content. Additionally, rice P uptake was significantly increased upon exposure to 1T and 2H MoS₂ (10 mg kg^-1). Gas chromatography-mass spectrometry (GC-MS) reveals that both phases of MoS₂ in soil systematically enhanced the carbon and nitrogen related metabolic pathways in exposed plants. Soil 16S rRNA gene sequencing data show that soil microbial community structure was unchanged upon MoS₂ exposure. However, both phases of MoS₂ remarkably increased the relative abundance of N₂-fixation cyanobacteria, and 2H MoS₂ exposure increased a plant growth-promoting rhizobacteria-Bacillus. Overall, our results suggest that MoS₂ nanosheets at tested doses did not exert negative impacts on rice plant and the associated soil microbial community.

Controlled decoration of nanoceria on the surface of MoS2nanoflowers to improve the biodegradability and biocompatibility inDrosophila melanogastermodel

In recent years, nanozymes based on two-dimensional (2D) nanomaterials have been receiving great interest for cancer photothermal therapy. 2D materials decorated with nanoparticles (NPs) on their surface are advantageous over conventional NPs and 2D material based systems because of their ability to synergistically improve the unique properties of both NPs and 2D materials. In this work, we report a nanozyme based on flower-like MoS₂nanoflakes (NFs) by decorating their flower petals with NCeO₂using polyethylenimine (PEI) as a linker molecule. A detailed investigation on toxicity, biocompatibility and degradation behavior of fabricated nanozymes in wild-typeDrosophila melanogastermodel revealed that there were no significant effects on the larval size, morphology, larval length, breadth and no time delay in changing larvae to the third instar stage at 7-10 d for MoS₂NFs before and after NCeO₂decoration. The muscle contraction and locomotion behavior of third instar larvae exhibited high distance coverage for NCeO₂decorated MoS₂NFs when compared to bare MoS₂NFs and control groups. Notably, the MoS₂and NCeO₂-PEI-MoS₂NFs treated groups at 100μg ml^-1covered a distance of 38.2 mm (19.4% increase when compared with control) and 49.88 mm (no change when compared with control), respectively. High-resolution transmission electron microscopy investigations on the new born fly gut showed that the NCeO₂decoration improved the degradation rate of MoS₂NFs. Hence, nanozymes reported here have huge potential in various fields ranging from biosensing, cancer therapy and theranostics to tissue engineering and the treatment of Alzheimer's disease and retinal therapy.

In situ grown bacterial cellulose/MoS2 composites for multi-contaminant wastewater treatment and bacteria inactivation

For the purpose of developing multifunctional water purification materials capable of degrading organic pollutants while simultaneously inactivating microorganisms from contaminated wastewater streams, we report here a facile and eco-friendly method to immobilize molybdenum disulfide into bacterial cellulose via a one-step in-situ biosynthetic method. The resultant nanocomposite, termed BC/MoS₂, was shown to possess a photocatalytic activity capable of generating •OH from H₂O₂, while also exhibiting photodynamic/photothermal mechanisms, the combination of which exhibits synergistic activity for the degradation of pollutants as well as for bacterial inactivation. In the presence of H₂O₂, the BC/MoS₂ nanocomposite exhibited excellent antibacterial efficacy upwards of 99.9999% (6 log units) for the photoinactivation of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus upon infrared (IR) lamp illumination (100 W, 760 nm ≤ λ ≤ 5000 nm, 15 cm vertical distance; 5 min). Mechanistic studies revealed synergistic pathogen inactivation resulting from the combination of photocatalytically generated •OH and hyperthermia induced by the photothermal conversion of the near-IR light. In addition, the BC/MoS₂ nanocomposite also showed excellent photodegradation activity for common aqueous contaminants in the presence of H₂O₂, including malachite green (a textile dye), catechol violet (a phenol) and formaldehyde. Taken together, our findings demonstrate that sustainable materials such as BC/MoS₂ have potential applications in wastewater treatment and microorganism disinfection.

Tungsten disulfide nanotubes enhance flow-induced crystallization and radio-opacity of polylactide without adversely affecting in vitro toxicity

Treatment of vascular disease, from peripheral ischemia to coronary heart disease (CHD), is poised for transformation with the introduction of transient implants designed to "scaffold" regeneration of blood vessels and ultimately leave nothing behind. Improved materials could expand the use of these devices. Here, we examine one of the leading polymers for bioresorbable scaffolds (BRS), polylactide (PLA), as the matrix of nanocomposites with tungsten disulfide (WS₂) nanotubes (WSNT), which may provide mechanical reinforcement and enhance radio-opacity. We evaluate in vitro cytotoxicity using vascular cells, flow-induced crystallization and radio-opacity of PLA-WSNT nanocomposites at low WSNT concentration. A small amount of WSNT (0.1 wt%) can effectively promote oriented crystallization of PLA without compromising molecular weight. And radio-opacity improves significantly: as little as 0.5 to 1 wt% WSNT doubles the radio-opacity of PLA-WSNT relative to PLA at 17 keV. The results suggest that a single component, WSNT, has the potential to increase the strength of BRS to enable thinner devices and increase radio-opacity to improve intraoperative visualization. The in vitro toxicity results indicate that PLA-WSNT nanocomposites are worthy of investigation in vivo. Although substantial further preclinical studies are needed, PLA-WSNT nanocomposites may provide a complement of material properties that may improve BRS and expand the range of lesions that can be treated using transient implants. STATEMENT OF SIGNIFICANCE: Bioresorbable Scaffolds (BRSs) support regeneration of arteries without permanent mechanical constraint. Poly-L-lactide (PLLA) is the structural material of the first approved BRS for coronary heart disease (ABSORB BVS), withdrawn due to adverse events in years 1-3. Here, we examine tungsten disulfide (WS₂) nanotubes (WSNT) in PLA to address two contributors to early complications: (1) reinforce PLLA (enable thinner BRS), and (2) increase radiopacity (provide intraoperative visibility). For BRS, it is significant that WSNT disperse, remain dispersed, reduce friction and improve mechanical properties without additional chemicals or surface modifications. Like WS₂ nanospheres, bare WSNT and PLA-WSNT nanocomposites show low cytotoxicity in vitro. PLA-WSNT show enhanced flow-induced crystallization relative to PLA, motivating future study of the processing behavior and strength of these materials.

Bionanohybrid composed of metalloprotein/DNA/MoS2/peptides to control the intracellular redox states of living cells and its applicability as a cell-based biomemory device

The development of cell-based bioelectronic devices largely depends on the direct control of intracellular redox states. However, most related studies have focused on the accurate measurement of electrical signals from living cells, whereas direct intracellular state control remains largely unexplored. Here, we developed a biocompatible transmembranal bionanohybrid structure composed of a recombinant metalloprotein, DNA, molybdenum disulfide nanoparticles (MoS₂), and peptides to control intracellular redox states, which can be used as a cell-based biomemory device. Using the capacitance of MoS₂ located inside the cell, the bionanohybrid controled the intracellular redox states of living cells by recording and extracting intracellular charges, which inturn was achieved by activating (writing) and deactivating (erasing) the cells. As a proof of concept, cell-based biomemory functions including writing, reading, and erasing were successfully demonstrated and confirmed via electrochemical methods and patch-clamp analyses, resulting in the development of the first in vitro cell-based biomemory device. This newly developed bionanohybrid provides a novel approach to control cellular redox states for cell-based bioelectronic applications, and can be applicable in a wide range of biological fields including bioelectronic medicine and intracellular redox status regulation.

Pulmonary toxicity, genotoxicity, and carcinogenicity evaluation of molybdenum, lithium, and tungsten: A review

Molybdenum, lithium, and tungsten are constituents of many products, and exposure to these elements potentially occurs at work. Therefore it is important to determine at what levels they are toxic, and thus we set out to review their pulmonary toxicity, genotoxicity, and carcinogenicity. After pulmonary exposure, molybdenum and tungsten are increased in multiple tissues; data on the distribution of lithium are limited. Excretion of all three elements is both via faeces and urine. Molybdenum trioxide exerted pulmonary toxicity in a 2-year inhalation study in rats and mice with a lowest-observed-adverse-effect concentration (LOAEC) of 6.6 mg Mo/m³. Lithium chloride had a LOAEC of 1.9 mg Li/m³ after subacute inhalation in rabbits. Tungsten oxide nanoparticles resulted in a no-observed-adverse-effect concentration (NOAEC) of 5 mg/m³ after inhalation in hamsters. In another study, tungsten blue oxide had a LOAEC of 63 mg W/m³ in rats. Concerning genotoxicity, for molybdenum, the in vivo genotoxicity after inhalation remains unknown; however, there was some evidence of carcinogenicity of molybdenum trioxide. The data on the genotoxicity of lithium are equivocal, and one carcinogenicity study was negative. Tungsten seems to have a genotoxic potential, but the data on carcinogenicity are equivocal. In conclusion, for all three elements, dose descriptors for inhalation toxicity were identified, and the potential for genotoxicity and carcinogenicity was assessed.