2D MoS2 Nanostructures for Biomedical Applications

Photoresponsive and Shape-Switchable MoS2-Peptide-Hybrid Nanosystems for Enacting Photochemo and siRNA-Mediated Gene Therapy in Glioma

Exfoliated 2D transition-metal dichalcogenide (TMDCs)-based nanomaterials have captured a huge biomedical territory owing to their supreme physicochemical properties. However, the tedious and harsh chemical exfoliation of bulk MoS2 impacts its utility in the biological domain. The study introduces a facile and environmentally benign way of shape-tunable exfoliation of bulk MoS2 materials in an aqueous dispersion using designed self-assembled, tetrapeptide (Fmoc-HCKF-OH)-based nanostructures, generating hybrid MoS2-peptide nanosystems for both tumor-targeted [employing folic acid (FA) functionalization] and NIR-responsive delivery of anticancer siRNA/drug in glioma. Exfoliated MoS2-peptide NSs here prove to be an excellent photothermal agent by inducing a temperature elevation upto ∼51 °C upon 808 nm NIR absorption. Enhanced siRNA/Dox loading onto the 2D flat morphology of MoS2-peptide NSs resulted in ∼90% cancer cell death in C6 glioma cells under NIR exposure. The expression of the Galectin-1 oncogene was suppressed following the treatment. Thereafter, analysis in the C6 glioma syngeneic rat model demonstrated a significant reduction (>10 fold) in tumor volume with siRNA/Dox-loaded FA-MoS2-peptide NSs + NIR as compared to the phosphate buffer saline-treated control group. Further, in vivo biodistribution studies confirmed the higher targetability of FA-conjugated hybrid NSs. Taken together, our findings promote the utility of TMDC-based nanomaterials in conjecture with a biocompatible peptide scaffold as a trimodal chemo, gene, and phototherapeutic agent.

Engineered molybdenum disulfide nanosheets as scavengers against oxidative stress inhibit ferroptosis to alleviate acute kidney injury

Acute kidney injury (AKI) is a common clinical kidney dysfunction associated with high morbidity, elevated mortality, and poor prognosis. It results from redox imbalance caused by abnormal excess production of endogenous reactive oxygen species (ROS) at the renal tubules, which in turn initiates a series of pathological processes, such as cellular apoptosis, necrosis, and ferroptosis, eventually leading to structural and functional impairment of the kidney. Thereinto, ferroptosis induced by the lethal accumulation of lipid peroxidation is extensively involved in renal damage. Nanotechnology-mediated therapeutic strategies to scavenge excessive ROS and thereby inhibit ferroptosis represents a promising strategy for AKI management. Herein, we report two engineered ultrathin molybdenum disulfide (MoS2) nanosheets (NSs) modified with polyvinylpyrrolidone (PVP) and bovine serum albumin (BSA), respectively, with excellent biocompatibility and antioxidative defense capability for AKI treatment. The engineered NSs, with a readily variable valence state of molybdenum ions, rescued cell viability by consuming various forms of cellular ROS and significantly facilitated glutathione peroxidase 4 (GPX4) expression to mitigate ferroptosis in renal tubular epithelial cells. In a glycerol-induced AKI mouse model, the PVP-MoS2 NSs were largely accumulated in the injured kidneys, where they provided robust antioxidative protection against ROS attack and suppressed the oxidative stress-induced inflammatory response, thereby maintaining normal kidney function. Of the two engineered NSs, PVP-MoS2 displayed superior biological stability and therapeutic effects and could thus serve as a powerful antioxidant platform for use in the treatment of AKI and other ROS-associated diseases. This study underscores the potential of two-dimensional nanomaterials in precisely treating AKI and other ferroptosis-related diseases.

Transition Metal Dichalcogenides in Biomedical Devices and Biosensors: A New Frontier for Precision Healthcare

Transition metal dichalcogenides (TMDs) have emerged as groundbreaking materials in the field of biomedical applications, particularly in the development of biosensors and medical devices. Their unique electronic and optical properties, combined with their tunability and biocompatibility, position TMDs as promising candidates for enhancing early disease detection and enabling personalized medicine. This perspective explores the multifaceted potential of TMDs, highlighting their applications in fluorescence and Raman-based biosensing, wearable and implantable devices, and smart therapeutic systems for targeted treatment. Additionally, we address critical challenges such as regulatory hurdles, long-term stability, and ethical considerations surrounding continuous health monitoring and data privacy. Looking to the future, we envision TMDs playing a vital role in the advancement of precision medicine, facilitating real-time health monitoring and individualized treatments. However, the successful integration of TMDs into clinical practice necessitates interdisciplinary collaboration among materials science, bioengineering, and clinical medicine. By fostering such collaboration, we can fully harness the capabilities of TMDs to revolutionize healthcare, making it more accessible, precise, and personalized for patients worldwide.

Janus and Amphiphilic MoS2 2D Sheets for Surface-Directed Orientational Assemblies toward Ex Vivo Dual Substrate Release

The two-dimensional (2-D) Janus and amphiphilic molybdenum disulfide (MoS2) nanosheet with opposite optical activities on each side (amphichiral) is synthesized by modifying sandwich-like bulk MoS2 with tannic acid and cholesterol through biphasic emulsion method. This new type of amphichiral Janus MoS2 nanosheet consists of a hydrophilic and positive optical activity tannic acid side as well as a hydrophobic and negative optical activity cholesterol side thereby characterized by circular dichroism. Surface-directed orientational differentiation assemblies are performed for the as-synthesized 2D material and are characterized by contact angle, infrared spectroscopy, X-ray photoelectron, and circular dichroism spectroscopies. The amphiphilic nature of the materials is demonstrated by the pre-organization of the nanosheets on either hydrophobic or hydrophilic surfaces, providing unprecedented properties of circular dichroism signal enhancement and wettability. Selective detachment of the surface organic groups (cholesterol and tannic acid fragments) is realized by matrix-assisted laser desorption/ionisation - time-of-flight (MALDI-TOF) mass spectrometry, and the dual substrate release in tissue is detected by ex vivo mass spectrometry imaging.

Molecular dynamics simulations reveal concentration-dependent blockage of graphene quantum dots to water channel protein openings

Graphene quantum dots (GQDs) have attracted significant attention across various scientific research areas due to their exceptional properties. However, studies on the potential toxicity of GQDs have yielded conflicting results. Therefore, a comprehensive evaluation of the toxicity profile of GQDs is essential for a thorough understanding of their biosafety. In this work, employing a molecular dynamics (MD) simulation approach, we investigate the interactions between GQDs and graphene oxide quantum dots (GOQDs) with the AQP1 water channel protein, aiming to explore the potential biological influence of GQDs/GOQDs. Our MD simulation results reveal that GQDs can adsorb to the loop region around the openings of AQP1 water channels, resulting in the blockage of these channels and potential toxicity. Interestingly, this blockage is concentration-dependent, with higher GQD concentrations leading to a greater likelihood of blockage. Additionally, GOQDs show a lower probability of blocking the openings of AQP1 water channels compared to GQDs, due to the hydrophobicity of the loop regions around the openings, which ultimately leads to lower interaction energy. Therefore, these findings provide new insights into the potential adverse impact of GQDs on AQP1 water channels through the blockage of their openings, offering valuable molecular insights into the toxicity profile of GQD nanomaterials.

Advanced materials for micro/nanorobotics

Autonomous micro/nanorobots capable of performing programmed missions are at the forefront of next-generation micromachinery. These small robotic systems are predominantly constructed using functional components sourced from micro- and nanoscale materials; therefore, combining them with various advanced materials represents a pivotal direction toward achieving a higher level of intelligence and multifunctionality. This review provides a comprehensive overview of advanced materials for innovative micro/nanorobotics, focusing on the five families of materials that have witnessed the most rapid advancements over the last decade: two-dimensional materials, metal-organic frameworks, semiconductors, polymers, and biological cells. Their unique physicochemical, mechanical, optical, and biological properties have been integrated into micro/nanorobots to achieve greater maneuverability, programmability, intelligence, and multifunctionality in collective behaviors. The design and fabrication methods for hybrid robotic systems are discussed based on the material categories. In addition, their promising potential for powering motion and/or (multi-)functionality is described and the fundamental principles underlying them are explained. Finally, their extensive use in a variety of applications, including environmental remediation, (bio)sensing, therapeutics, etc., and remaining challenges and perspectives for future research are discussed.

Molybdenum disulfide nanosheets based non-oxygen-dependent and heat-initiated free radical nanogenerator with antimicrobial peptides for antimicrobial, biofilm ablation and wound healing

Chronic refractory wounds caused by multidrug-resistant (MDR) bacterial and biofilm infections are a substantial threat to human health, which presents a persistent challenge in managing clinical wound care. We here synthesized a composite nanosheet AIPH/AMP/MoS2, which can potentially be used for combined therapy because of the photothermal effect induced by MoS2, its ability to deliver antimicrobial peptides, and its ability to generate alkyl free radicals independent of oxygen. The synthesized nanosheets exhibited 61 % near-infrared (NIR) photothermal conversion efficiency, marked photothermal stability and free radical generating ability. The minimal inhibitory concentrations (MICs) of the composite nanosheets against MDR Escherichia coli (MDR E. coli) and MDR Staphylococcus aureus (MDR S. aureus) were approximately 38 μg/mL and 30 μg/mL, respectively. The composite nanosheets (150 μg/mL) effectively ablated >85 % of the bacterial biofilm under 808-nm NIR irradiation for 6 min. In the wound model experiment, approximately 90 % of the wound healed after the 4-day treatment with the composite nanosheets. The hemolysis experiment, mouse embryonic fibroblast (MEFs) cytotoxicity experiment, and mouse wound healing experiment all unveiled the excellent biocompatibility of the composite nanosheets. According to the transcriptome analysis, the composite nanosheets primarily exerted a synergistic therapeutic effect by disrupting the cellular membrane function of S. aureus and inhibiting quorum sensing mediated by the two-component system. Thus, the synthesized composite nanosheets exhibit remarkable antibacterial and biofilm ablation properties and therefore can be used to improve wound healing in chronic biofilm infections.

Facile synthesis of MoS2@red phosphorus heterojunction for synergistically photodynamic and photothermal therapy of renal cell carcinoma

The therapy of the clear cell renal cell carcinoma (ccRCC) is crucial for the human healthcare due to its easy metastasis and recurrence, as well as resistance to radiotherapy and chemotherapy. In this work, we propose the synthesis of MoS2@red phosphorus (MoS2@RP) heterojunction to induce synergistic photodynamic and photothermal therapy (PDT/PTT) of ccRCC. The MoS2@RP heterojunction exhibits enhanced spectra absorption in the NIR range and produce local heat-increasing under the NIR laser irradiation compared with pure MoS2 and RP. The high photocatalytic activity of the MoS2@RP heterojunction contributes to effective transferring of the photo-excited electrons from the RP to MoS2, which promotes the production of various types of radical oxygen species (ROS) to kill the ccRCC cells. After the NIR irradiation, the MoS2@RP can effectively induce the apoptosis in the ccRCC cells through localized hyperthermia and the generation of ROS, while exhibiting low cytotoxicity towards normal kidney cells. In comparison to MoS2, the MoS2@RP heterojunction shows an approximate increase of 22 % in the lethality rate of the ccRCC cells and no significant change in toxicity towards normal cells. Furthermore, the PDT/PTT treatment using the MoS2@RP heterojunction effectively eradicates a substantial number of deep-tissue ccRCC cells in vivo without causing significant damage to major organs. This study presents promising effect of the MoS2@RP heterojunction-based photo-responsive therapy for effective ccRCC treatment.

Recent developments in two-dimensional molybdenum disulfide-based multimodal cancer theranostics

Recent advancements in cancer research have led to the generation of innovative nanomaterials for improved diagnostic and therapeutic strategies. Despite the proven potential of two-dimensional (2D) molybdenum disulfide (MoS2) as a versatile platform in biomedical applications, few review articles have focused on MoS2-based platforms for cancer theranostics. This review aims to fill this gap by providing a comprehensive overview of the latest developments in 2D MoS2 cancer theranostics and emerging strategies in this field. This review highlights the potential applications of 2D MoS2 in single-model imaging and therapy, including fluorescence imaging, photoacoustic imaging, photothermal therapy, and catalytic therapy. This review further classifies the potential of 2D MoS2 in multimodal imaging for diagnostic and synergistic theranostic platforms. In particular, this review underscores the progress of 2D MoS2 as an integrated drug delivery system, covering a broad spectrum of therapeutic strategies from chemotherapy and gene therapy to immunotherapy and photodynamic therapy. Finally, this review discusses the current challenges and future perspectives in meeting the diverse demands of advanced cancer diagnostic and theranostic applications.

Biomedical prospects and challenges of metal dichalcogenides nanomaterials

The biomedical applications of metal dichalcogenides (MDCs) nanomaterials (NMs) are an emerging discipline because of their unique attributes like high surface-to-volume ratio, defect sites, superb catalytic performance, and excitation-dependent emission, which is helpful in bio-imaging and cancer cell killing. Due to the compatibility of sensing material with cells and tissues, MoS2, WS2, and SnS2NMs have piqued the interest of researchers in various biomedical applications like photothermal therapy used in killing cancer cells, drug delivery, photoacoustic tomography (PAT) used in bio-imaging, nucleic acid or gene delivery, tissue engineering, wound healing, etc. Furthermore, these NMs' functionalization and defect engineering can enhance therapeutic efficacy, biocompatibility, high drug transport efficiency, adjustable drug release, dispersibility, and biodegradability. Among the aforementioned materials, MoS2NMs have extensively been explored via functionalization and defects engineering to improve biosensing properties. However, further enhancement is still available. Aside from MoS2, the distinct chemo-physical and optical features of WS2and SnS2NMs promise considerable potential in biosensing, nanomedicine, and pharmaceuticals. This article mainly focuses on the challenges and future aspects of two-dimensional MDCs NMs in biomedical applications, along with their advancements in various medical diagnosis processes.

An Asymmetric NIR-II Organic Fluorophore with an Ultra-Large Stokes Shift for Imaging-Guided and Targeted Phototherapy

NIR-II imaging-guided phototherapy is an attractive, yet challenging, tumor treatment strategy. By monitoring the accumulation of phototherapy reagents at the tumor site through imaging and determining the appropriate therapy window, the therapeutic effect could be significantly improved. Probes with NIR-II (1000-1700 nm) fluorescence emission and a large Stokes shift hold great promise for fluorescence imaging with deep penetration, minimized self-quenching, and high spatiotemporal resolution. However, due to the lack of a suitable molecular framework, the design of a simple small-molecule dye with a large Stokes shift and NIR-II fluorescence emission has rarely been reported. Herein, we prepare an asymmetric D-π-A type NIR-II fluorescence probe (TBy). The probe is incapsulated in an amphiphilic polymer and modified with a fibronectin targeting peptide CREKA, which could recognize the fibrin-fibronectin complex overexpressed in multiple malignant tumors. The nanoparticles thus constructed (TByC-NPs) have maximum fluorescence emission at 1037 nm with a large Stokes shift of 426 nm, which is the largest Stokes shift among organic NIR-II fluorescent dyes reported in the literature. The TByC-NPs exhibit a good NIR-II imaging performance, active tumor targeting, and good photothermal and photodynamic capabilities. In vitro and in vivo studies verify that the TByC nanoplatform shows outstanding biocompatibility for NIR-II imaging-guided phototherapy and provides an excellent antitumor effect.

Chiral MoS2@BC fibrous membranes selectively promote peripheral nerve regeneration

BACKGROUND

Molybdenum disulfide (MoS2) has excellent physical and chemical properties. Further, chiral MoS2 (CMS) exhibits excellent chiroptical and enantioselective effects, and the enantioselective properties of CMS have been studied for the treatment of neurodegenerative diseases. Intriguingly, left- and right-handed materials have different effects on promoting the differentiation of neural stem cells into neurons. However, the effect of the enantioselectivity of chiral materials on peripheral nerve regeneration remains unclear.

METHODS

In this study, CMS@bacterial cellulose (BC) scaffolds were fabricated using a hydrothermal approach. The CMS@BC films synthesized with L-2-amino-3-phenyl-1-propanol was defined as L-CMS. The CMS@BC films synthesized with D-2-amino-3-phenyl-1-propanol was defined as D-CMS. The biocompatibility of CMS@BC scaffolds and their effect on Schwann cells (SCs) were validated by cellular experiments. In addition, these scaffolds were implanted in rat sciatic nerve defect sites for three months.

RESULTS

These chiral scaffolds displayed high hydrophilicity, good mechanical properties, and low cytotoxicity. Further, we found that the L-CMS scaffolds were superior to the D-CMS scaffolds in promoting SCs proliferation. After three months, the scaffolds showed good biocompatibility in vivo, and the nerve conducting velocities of the L-CMS and D-CMS scaffolds were 51.2 m/s and 26.8 m/s, respectively. The L-CMS scaffolds showed a better regenerative effect than the D-CMS scaffolds. Similarly, the sciatic nerve function index and effects on the motor and electrophysiological functions were higher for the L-CMS scaffolds than the D-CMS scaffolds. Finally, the axon diameter and myelin sheath thickness of the regenerated nerves were improved in the L-CMS group.

CONCLUSION

We found that the CMS@BC can promote peripheral nerve regeneration, and in general, the L-CMS group exhibited superior repair performance. Overall, the findings of this study reveal that CMS@BC can be used as a chiral nanomaterial nerve scaffold for peripheral nerve repair.

Molybdenum disulfide nanosheet induced reactive oxygen species for high-efficiency luminol chemiluminescence

BACKGROUND

Luminol chemiluminescence (CL) sensing system remains an excellent candidate for application in bioanalysis due to its good water solubility. However, traditional luminol CL system usually requires the addition of oxidizing agents and sensitizers to obtain high efficiency for the improvement of detection sensitivity. Although numerous studies on the nanomaterial-enhanced luminol CL systems have been carried out, there is still great potential to develop inexpensive, readily available and easily handled catalysts to construct simple and effective CL platform for biomolecular sensing.

RESULTS

Few-layered MoS2 nanosheets (NS) prepared by sonication-assisted exfoliation of commercially available bulk MoS2 were found to significantly enhance the CL of luminol‒dissolved oxygen in the absence of additional oxidants. The mechanism study demonstrated that exfoliated MoS2 NS could catalyze the decomposition of dissolved oxygen by virtue of its exposed active sites on the surface, generating increased reactive oxygen intermediates, which then oxidize luminol and produce intense CL emission. The proposed high-efficiency luminol CL system was then employed for the extremely sensitive identification of dopamine based on the quenching of CL by dopamine. The limit of detection (LOD) for dopamine can be as low as 2.07 nM. Besides, it also works well in the actual urine sample with good recoveries (99.6-100.6 %), confirming the practicability of the method.

SIGNIFICANCE

As a new type of CL catalyst, MoS2 NS developed in this work are easy to obtain, simple to prepare and can be produced in large quantities, which lays a foundation for extending applicability of MoS2 NS in the CL field, and provides a new idea for developing simple and highly sensitive CL sensing system.

Polydopamine-Modified 2D Iron (II) Immobilized MnPS3 Nanosheets for Multimodal Imaging-Guided Cancer Synergistic Photothermal-Chemodynamic Therapy

Manganese phosphosulphide (MnPS3 ), a newly emerged and promising member of the 2D metal phosphorus trichalcogenides (MPX3 ) family, has aroused abundant interest due to its unique physicochemical properties and applications in energy storage and conversion. However, its potential in the field of biomedicine, particularly as a nanotherapeutic platform for cancer therapy, has remained largely unexplored. Herein, a 2D "all-in-one" theranostic nanoplatform based on MnPS3 is designed and applied for imaging-guided synergistic photothermal-chemodynamic therapy. (Iron) Fe (II) ions are immobilized on the surface of MnPS3 nanosheets to facilitate effective chemodynamic therapy (CDT). Upon surface modification with polydopamine (PDA) and polyethylene glycol (PEG), the obtained Fe-MnPS3 /PDA-PEG nanosheets exhibit exceptional photothermal conversion efficiency (η = 40.7%) and proficient pH/NIR-responsive Fenton catalytic activity, enabling efficient photothermal therapy (PTT) and CDT. Importantly, such nanoplatform can also serve as an efficient theranostic agent for multimodal imaging, facilitating real-time monitoring and guidance of the therapeutic process. After fulfilling the therapeutic functions, the Fe-MnPS3 /PDA-PEG nanosheets can be efficiently excreted from the body, alleviating the concerns of long-term retention and potential toxicity. This work presents an effective, precise, and safe 2D "all-in-one" theranostic nanoplatform based on MnPS3 for high-efficiency tumor-specific theranostics.

Interaction of 2D nanomaterial with cellular barrier: Membrane attachment and intracellular trafficking

The cell membrane serves as a barrier against the free entry of foreign substances into the cell. Limited by factors such as solubility and targeting, it is difficult for some drugs to pass through the cell membrane barrier and exert the expected therapeutic effect. Two-dimensional nanomaterial (2D NM) has the advantages of high drug loading capacity, flexible modification, and multimodal combination therapy, making them a novel drug delivery vehicle for drug membrane attachment and intracellular transport. By modulating the surface properties of nanocarriers, it is capable of carrying drugs to break through the cell membrane barrier and achieve precise treatment. In this review, we review the classification of various common 2D NMs, the primary parameters affecting their adhesion to cell membranes, and the uptake mechanisms of intracellular transport. Furthermore, we discuss the therapeutic potential of 2D NMs for several major disorders. We anticipate this review will deepen researchers' understanding of the interaction of 2D NM drug carriers with cell membrane barriers, and provide insights for the subsequent development of novel intelligent nanomaterials capable of intracellular transport.

2D Materials for Combination Therapy to Address Challenges in the Treatment of Cancer

2D materials exhibit a variety of characteristics that make them appealing platforms for cancer treatment such as high drug loading capacity and photothermal and photodynamic properties. A key advantage of 2D material platforms for oncological applications is the ability to harness multiple modalities including drug delivery, photothermal therapy, photodynamic therapy, chemodynamic therapy, gene delivery, and immunotherapy approaches for improved efficacy. In this review, a comparison of the unique properties of different classes of 2D materials that enable their usage as platforms for multimodal therapy is provided. Further, the benefits and drawbacks of different platforms are also highlighted. Finally, current challenges and emerging opportunities for future development of 2D materials to further enable combination therapy and translation from the bench to clinical oncology applications are discussed.

Chirality-Dependent Angiogenic Activity of MoS2 Quantum Dots toward Regulatable Tissue Regeneration

Despite great advances in understanding the biological behaviors of chiral materials, the effect of chirality-configured nanoparticles on tissue regeneration-related biological processes remains poorly understood. Herein, the chirality of MoS2 quantum dots (QDs) is tailored by functionalization with l-/d-penicillamine, and the profound chiral effects of MoS2 QDs on cellular activities, angiogenesis, and tissue regeneration are thoroughly investigated. Specifically, d-MoS2 QDs show a positive effect in promoting the growth, proliferation, and migration of human umbilical vein endothelial cells. The expression of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), and fibroblast growth factor (FGF) in d-MoS2 QDs group is substantially up-regulated, resulting in enhanced tube formation activity. This distinct phenomenon is largely due to the higher internalization efficiency of d-MoS2 QDs than l-MoS2 QDs and chirality-dependent nano-bio interactions. In vivo angiogenic assay shows the expression level of angiogenic markers in newly-formed skin tissues of d-MoS2 QDs group is higher than that in l-MoS2 QDs group, leading to an accelerated re-epithelialization and improved skin regeneration. The findings of chirality-dependent angiogenesis activity of MoS2 QDs provide new insights into the biological activity of MoS2 nanomaterials, which also opens up a new path to the rational design of chiral nanomaterials for tissue regeneration application.

Construction of CpG Delivery Nanoplatforms by Functionalized MoS2 Nanosheets for Boosting Antitumor Immunity in Head and Neck Squamous Cell Carcinoma

Despite the promising achievements of immune checkpoint blockade (ICB) therapy for tumor treatment, its therapeutic effect against solid tumors is limited due to the suppressed tumor immune microenvironment (TIME). Herein, a series of polyethyleneimine (Mw = 0.8k, PEI0.8k )-covered MoS2 nanosheets with different sizes and charge densities are synthesized, and the CpG, a toll-like receptor-9 agonist, is enveloped to construct nanoplatforms for the treatment of head and neck squamous cell carcinoma (HNSCC). It is proved that functionalized nanosheets with medium size display similar CpG loading capacity regardless of low or high PEI0.8k coverage owing to the flexibility and crimpability of 2D backbone. CpG-loaded nanosheets with medium size and low charge density (CpG@MM -PL ) could promote the maturation, antigen-presenting capacity, and proinflammatory cytokines generation of bone marrow-derived dendritic cells (DCs). Further analysis reveals that CpG@MM -PL effectively boosts the TIME of HNSCC in vivo including DC maturation and cytotoxic T lymphocyte infiltration. Most importantly, the combination of CpG@MM -PL and ICB agents anti-programmed death 1 hugely improves the tumor therapeutic effect, inspiring more attempts for cancer immunotherapy. In addition, this work uncovers a pivotal feature of the 2D sheet-like materials in nanomedicine development, which should be considered for the design of future nanosheet-based therapeutic nanoplatforms.

Targeted co-delivery of curcumin and erlotinib by MoS2 nanosheets for the combination of synergetic chemotherapy and photothermal therapy of lung cancer

BACKGROUND

Curcumin (Cur), a bioactive component of Chinese traditional medicine, has demonstrated inhibitory properties against cancer cell proliferation while synergistically enhancing the anticancer efficacy of erlotinib (Er). However, the individual limitations of both drugs, including poor aqueous solubility, lack of targeting ability, short half-life, etc., and their distinct pharmacokinetic profiles mitigate or eliminate their combined antitumor potential.

RESULTS

In this study, we developed a molybdenum disulfide (MoS2)-based delivery system, functionalized with polyethylene glycol (PEG) and biotin, and co-loaded with Cur and Er, to achieve efficient cancer therapy. The MoS2-PEG-Biotin-Cur/Er system effectively converted near-infrared (NIR) light into heat, thereby inducing direct photothermal ablation of cancer cells and promoting controlled release of Cur and Er. Biotin-mediated tumor targeting facilitated the selective accumulation of MoS2-PEG-Biotin-Cur/Er at the tumor site, thus enhancing the synergistic antitumor effects of Cur and Er. Remarkably, MoS2-PEG-Biotin-Cur/Er achieved the combination of synergistic chemotherapy and photothermal therapy (PTT) upon NIR irradiation, effectively suppressing lung cancer cell proliferation and inhabiting tumor growth in vivo.

CONCLUSIONS

The as-synthesized MoS2-PEG-Biotin-Cur/Er, featuring high targeting ability, NIR light-responsive drug release, and the integration of synergistic chemotherapy and PTT, may provide a promising strategy for the treatment of lung cancer in clinical practice.

Exposure to MoS2 nanosheets or bulk activated Kruppel-like factor 4 in 3D Caco-2 spheroids in vitro and mouse intestines in vivo

MoS2 nanosheets (NSs) are novel 2D nanomaterials (NMs) being used in many important fields. Recently, we proposed the need to evaluate the influences of NMs on Kruppel-like factors (KLFs) even if these materials are relatively biocompatible. In this study, we investigated the influences of MoS2 NSs or bulk on KLF4 signaling pathway in 3D Caco-2 spheroids in vitro and mouse intestines in vivo. Through the analysis of our previous RNA-sequencing data, we found that exposure to MoS2 NSs or bulk activated KLF4 expression in 3D Caco-2 spheroids. Consistently, these materials also activated KLF4-related gene ontology (GO) terms and down-regulated a panel of KLF4-downstream genes. To verify these findings, we repeatedly exposed mice to MoS2 NSs or bulk materials via intragastrical administration (1 mg/kg bodyweight, once a day, for 4 days). It was shown that oral exposure to these materials decreased bodyweight, leading to relatively higher organ coefficients. As expected, exposure to both types of materials increased Mo elements as well as other trace elements, such as Zn, Fe, and Mn in mouse intestines. The exposure also induced morphological changes of intestines, such as shortening of intestinal villi and decreased crypt depth, which may result in decreased intestinal lipid staining. Consistent with RNA-sequencing data, we found that material exposure increased KLF4 protein staining in mouse intestines and decreased two KLF4 downstream proteins, namely extracellular signal-regulated kinase (ERK) and serine/threonine kinase (AKT). We concluded that MoS2 materials were capable to activate KLF4-signaling pathway in intestines both in vivo and in vitro.

Protein-Assisted Molybdenum Disulfide as Biomimetic Nanozyme for Antibacterial Application

Molybdenum-based nanomaterials with variable oxidation states can be developed as nanozyme catalysts. In this work, we developed a one-pot method for the preparation of molybdenum disulfide assisted by protein. Protamine was used as a cationic template to link molybdate anions and form complexes. During hydrothermal synthesis, protamine can affect the nucleation process of molybdenum disulfide and inhibit their aggregation, which facilitates the fabrication of small-sized molybdenum disulfide nanoparticles. Moreover, the abundant amino/guanidyl groups of protamine could both physically adsorb and chemically bond to molybdenum disulfide and further modulate the crystal structures. The optimized size and crystalline structure enabled a higher exposure of active sites, which enhanced the peroxidase-like activity of molybdenum disulfide/protamine nanocomposites. Meanwhile, the antibacterial activity of protamine was retained in the molybdenum disulfide/protamine nanocomposites, which could synergize with the peroxidase-like activity of molybdenum disulfide to kill bacteria. Therefore, the molybdenum disulfide/protamine nanocomposites are good candidates for antibacterial agents with lower chances of antimicrobial resistance. This study establishes an easy way to design artificial nanozymes by compounding suitable components.

Wrapping-Trapping versus Extraction Mechanism of Bactericidal Activity of MoS2 Nanosheets against Staphylococcus aureus Bacterial Membrane

The promising broad-spectrum antibacterial activity of two-dimensional molybdenum disulfide (2D MoS₂) has been widely recognized in the past decade. However, a comprehensive understanding of how the antibacterial pathways opted by the MoS₂ nanosheets varies with change in lipid compositions of different bacterial strains is imperative to harness their full antibacterial potential and remains unexplored thus far. Herein, we present an atomistic molecular dynamics (MD) study to investigate the distinct modes of antibacterial action of MoS₂ nanosheets against Staphylococcus aureus (S. aureus) under varying conditions. We observed that the freely dispersed nanosheets readily adhered to the bacterial membrane outer surface and opted for an unconventional surface directed "wrapping-trapping" mechanism at physiological temperature (i.e., 310 K). The adsorbed nanosheets mildly influenced the membrane structure by originating a compact packing of the lipid molecules present in its direct contact. Interestingly, these surface adsorbed nanosheets exhibited extensive phospholipid extraction to their surface, thereby inducing transmembrane water passage analogous to the cellular leakage, even at a slight increment of 20 K in the temperature. The strong van der Waals interactions between lipid fatty acyl tails and MoS₂ basal planes were primarily responsible for this destructive phospholipid extraction. In addition, the MoS₂ nanosheets bound to an imaginary substrate, controlling their vertical alignment, demonstrated a "nano-knives" action by spontaneously piercing inside the membrane core through their sharp corner, subsequently causing localized lipid ordering in their vicinity. The larger nanosheet produced a more profound deteriorating impact in all of the observed mechanisms. Keeping the existing knowledge about the bactericidal activity of 2D MoS₂ in view, our study concludes that their antibacterial activity is strongly governed by the lipid composition of the bacterial membrane and can be intensified either by controlling the nanosheet vertical alignment or by moderately warming up the systems.

Long-term exposure of molybdenum disulfide nanosheets leads to hepatic lipid accumulation and atherogenesis in apolipoprotein E deficient mice

Before their large-scale applications, it is necessary to understand the biological effects of nanomaterials. Although two-dimensional nanomaterials (2D NMs) molybdenum disulfide nanosheets (MoS₂ NSs) are promising in biomedical fields, the current knowledge regarding their toxicities is inadequate. Using apolipoprotein E deficient (ApoE^-/-) mice as a long-term exposure model, this study demonstrated that intravenous (i.v.) injection of MoS₂ NSs most accumulated in the liver and caused in situ hepatic damage. Histopathological examination indicated severe infiltration of inflammatory cells and irregular central veins in the MoS₂ NSs-treated mouse liver. Meanwhile, the overwhelming expressions of inflammatory cytokines, dyslipidemia, and dysregulated hepatic lipid metabolism implied the potential vascular toxicity of MoS₂ NSs. Indeed, our result supported that MoS₂ NSs exposure is highly associated with atherosclerotic progression. This study provided the first line of evidence on the vascular toxicity of MoS₂ NSs, which remind scientists to pay attention to the rational use of MoS₂ NSs, especially in the biomedical fields.

Biomimetic Molybdenum Sulfide-Catalyzed Tumor Ferroptosis and Bioimaging

The chemical generation of singlet oxygen (1 O2 ) by the MoO4 2- -catalyzed disproportionation of hydrogen peroxide (H2 O2 ) has been widely applied in numerous catalytic processes; however, such molybdate ions cannot be administered for redox-based cancer therapeutics. This work reports the albumin-mediated biomimetic synthesis of highly active molybdenum sulfide (denoted MoB) nanocatalysts that mediate the simultaneous generation of 1 O2 and superoxide anion (O2 •- ) from H2 O2 , which is relatively abundant in malignant tumors. The MoB-catalyzed reactive oxygen species (ROS) are able to activate the ferroptosis pathway and cause lipid peroxidation for efficient cancer therapy. Furthermore, for the first time, the catalytic activity of MoB is visualized in situ. Moreover, a catalytic imaging modality based on MoB is developed for specific imaging of inflammation diseases without background interference. Therefore, this study presents a biomimetic strategy toward Mo-based nanocatalysts for ROS-facilitated tumor ferroptosis and catalytic imaging.

2D MoS2 and BN Nanosheets Damage Mitochondria through Membrane Penetration

With the progression of nanotechnology, a growing number of nanomaterials have been created and incorporated into organisms and ecosystems, which raises significant concern about potential hazards of these materials on human health, wildlife, and the environment. Two-dimensional (2D) nanomaterials are one type of nanomaterials with thicknesses ranging from that of a single atom or of several atoms and have been proposed for a variety of biomedical applications such as drug delivery and gene therapy, but the toxicity thereof on subcellular organelles remains to be studied. In this work, we studied the impact of two typical 2D nanomaterials, MoS₂ and BN nanosheets, on mitochondria, which are a type of membranous subcellular organelle that provides energy to cells. While 2D nanomaterials at a low dose exhibited a negligible cell mortality rate, significant mitochondrial fragmentation and partially reduced mitochondrial functions occurred; cells initiate mitophagy in response to mitochondrial damages, which cleans damaged mitochondria to avoid damage accumulation. Moreover, the molecular dynamics simulation results revealed that both MoS₂ and BN nanosheets can spontaneously penetrate the mitochondrial lipid membrane through the hydrophobic interaction. The membrane penetration induced heterogeneous lipid packing resulting in damages. Our results demonstrate that even at a low dose 2D nanomaterials can physically damage mitochondria by penetrating the membrane, which draws attention to carefully evaluating the cytotoxicity of 2D nanomaterials for the potential biomedical application.

Environmental implication of MoS2 nanosheets: Effects on maize plant growth and soil microorganisms

Molybdenum disulfide (MoS₂) nanosheets have been used extensively in a variety of fields including medical and industrial. However, little is known about their toxicity effects, especially to edible plants. In this greenhouse study, maize (Zea mays) seedlings were exposed for 4 weeks, through the soil route, to 10 and 100 mg/kg of 2H MoS₂ nanosheets. Plant growth, physiological parameters (chlorophyll, antioxidants, and MDA), along with Mo and nutrient element contents were determined in plant tissues. Results showed that at both doses, the nanosheets decreased plant growth. Inductively coupled plasma-mass spectrometry data also showed that both 2H MoS₂ concentrations allowed Mo absorption and translocation by maize plants. Additionally, at 100 mg/kg the nanosheets significantly reduced Ca, Mg, Mn, and Zn in leaves, and Na in roots. Gene sequencing data of 16S rRNA showed, that MoS₂ nanosheets changed the soil microbial community structure, compared with the untreated control. In addition, nitrogen-fixing microorganisms such as Burkholderiales, Rhizobiales and Xanthobacteraceae were enriched. Overall, the data suggest that, even at low dose (10 mg/kg), the 2H MoS₂ nanosheets perturbed both the nutrient uptake by maize plants and the soil microbial communities.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

Polygonal gold nanocrystal induced efficient phase transition in 2D-MoS2for enhancing photo-electrocatalytic hydrogen generation

Plasmonic nanocrystals (NCs) assisted phase transition of two-dimensional molybdenum disulfide (2D-MoS₂) unlashes numerous opportunities in the fields of energy harvesting via electrocatalysis and photoelectrocatalysis by enhancing electronic conductivity, increasing catalytic active sites, lowering Gibbs free energy for hydrogen adsorption and desorption, etc. Here, we report the synthesis of faceted gold pentagonal bi-pyramidal (Au-PBP) nanocrystals (NC) for efficient plasmon-induced phase transition (from 2 H to 1 T phase) in chemical vapor deposited 2D-MoS₂. The as-developed Au-PBP NC with the increased number of corners and edges showed an enhanced multi-modal plasmonic effect under light irradiations. The overpotential of hydrogen evolution reaction (HER) was reduced by 61 mV, whereas the Tafel slope decreased by 23.7 mV/dec on photoexcitation of the Au-PBP@MoS₂hybrid catalyst. The enhanced performance can be attributed to the light-induced 2H to 1 T phase transition of 2D-MoS₂, increased active sites, reduced Gibbs free energy, efficient charge separation, change in surface potential, and improved electrical conductivity of 2D-MoS₂film. From density functional theory (DFT) calculations, we obtain a significant change in the electronic properties of 2D-MoS₂(i.e. work function, surface chemical potential, and the density of states), which was primarily due to the plasmonic interactions and exchange-interactions between the Au-PBP nanocrystals and monolayer 2D-MoS₂, thereby enhancing the phase transition and improving the surface properties. This work would lay out finding assorted routes to explore more complex nanocrystals-based multipolar plasmonic NC to escalate the HER activity of 2D-MoS₂and other 2D transition metal dichalcogenides.

Combined Photodynamic and Photothermal Therapy and Immunotherapy for Cancer Treatment: A Review

Photoactivation therapy based on photodynamic therapy (PDT) and photothermal therapy (PTT) has been identified as a tumour ablation modality for numerous cancer indications, with photosensitisers and photothermal conversion agents playing important roles in the phototherapy process, especially in recent decades. In addition, the iteration of nanotechnology has strongly promoted the development of phototherapy in tumour treatment. PDT can increase the sensitivity of tumour cells to PTT by interfering with the tumour microenvironment, whereas the heat generated by PTT can increase blood flow, improve oxygen supply and enhance the PDT therapeutic effect. In addition, tumour cell debris generated by phototherapy can serve as tumour-associated antigens, evoking antitumor immune responses. In this review, the research progress of phototherapy, and its research effects in combination with immunotherapy on the treatment of tumours are mainly outlined, and issues that may need continued attention in the future are raised.

Biomimetic 3D Recognition with 2D Flexible Nanoarchitectures for Ultrasensitive and Visual Extracellular Vesicle Detection

Despite increasing recognition of extracellular vesicles being important circulating biomarkers in disease diagnosis and prognosis, current strategies for extracellular vesicle detection remain limited due to the compromised sample purification and extensive labeling procedures in complex body fluids. Here, we developed a 2D magnetic platform that greatly improves capture efficiency and readily realizes visible signal conversion for extracellular vesicle detection. The technology, termed high-affinity recognition and visual extracellular vesicle testing (HARVEST), leverages 2D flexible Fe₃O₄-MoS₂ nanostructures to recognize extracellular vesicles through multidentate affinity binding and feasible magnetic separation, thus enhancing the extracellular vesicle capture performance with both yield and separation time, affording high sensitivity with the detection limit of 20 extracellular vesicle particles/μL. Through integration with lipid labeling chemistry and the fluorescence visualization system, the platform enables rapid and visible detection. The number of extracellular vesicles can be feasibly determined by smart mobile phones, readily adapted for point-of-care diagnosis. When clinically evaluated, the strategy accurately differentiates melanoma samples from the normal cohort with an AUC of 0.98, demonstrating the efficient extracellular vesicle detection strategy with 2D flexible platforms for cancer diagnosis.

Advances in Novel Nanomaterial-Based Optical Fiber Biosensors-A Review

This article presents a concise summary of current advancements in novel nanomaterial-based optical fiber biosensors. The beneficial optical and biological properties of nanomaterials, such as nanoparticle size-dependent signal amplification, plasmon resonance, and charge-transfer capabilities, are widely used in biosensing applications. Due to the biocompatibility and bioreceptor combination, the nanomaterials enhance the sensitivity, limit of detection, specificity, and response time of sensing probes, as well as the signal-to-noise ratio of fiber optic biosensing platforms. This has established a practical method for improving the performance of fiber optic biosensors. With the aforementioned outstanding nanomaterial properties, the development of fiber optic biosensors has been efficiently promoted. This paper reviews the application of numerous novel nanomaterials in the field of optical fiber biosensing and provides a brief explanation of the fiber sensing mechanism.

Fe-Doped MoS2 Nanozyme for Antibacterial Activity and Detoxification of Mustard Gas Simulant

The peroxidase-like catalytic activity of various nanozymes was extensively applied in various fields. In this study, we have demonstrated the preparation of Fe-doped MoS₂ (Fe@MoS₂) nanomaterials with enhanced peroxidase-like activity of MoS₂ in a co-catalytic pathway. In view of Fenton reaction, the peroxidase-like Fe@MoS₂ nanozyme prompted the decomposition of hydrogen peroxide (H₂O₂) to a reactive hydroxyl radical (·OH). The efficient decomposition of H₂O₂ in the presence of Fe@MoS₂ has been employed toward the antibacterial activity and detoxification of mustard gas simulant. The combined effect of Fe@MoS₂ and H₂O₂ showed remarkable antibacterial activity against the drug-resistant bacterial strain methicillin-resistant Staphylococcus aureus and Escherichia coli with the use of minimal concentration of H₂O₂. Fe@MoS₂ was further applied for the detoxification of the chemical warfare agent sulfur mustard simulant, 2-chloroethyl ethyl sulfide, by selective conversion to the nontoxic sulfoxide. This work demonstrates the development of a hybrid nanozyme and its environmental remediation from harmful chemicals to microbes.

Enhanced Room Temperature Ammonia Gas Sensing Properties of Fe-Doped MoO3 Thin Films Fabricated Using Nebulizer Spray Pyrolysis

MoO₃ thin films are fabricated using nebulizer spray pyrolysis technique, which is doped with Fe at various concentrations of 1, 2, 3, and 4% for ammonia gas sensors application at room temperature. X-ray diffraction (XRD) study confirms the growth of the crystal by Fe doping up to 3%, nano rods shape morphology of the thin film samples observed by field emission scanning electron microscope (FESEM), reduction in bandgap is evidenced via UV-VIS spectrophotometer. Gas sensing study is performed using gas analyzing chamber attached with Keithley source meter. Since 3% Fe doped MoO₃ sample displayed nano rods over the film surface which exhibits highest sensitivity of 38,500%, in a short period of raise and decay time 54 and 6 s. Our findings confirms that the 3% Fe doped MoO₃ films suitability for ammonia gas sensing application.

Embellishing 2-D MoS2 Nanosheets on Lotus Thread Devices for Enhanced Hydrophobicity and Antimicrobial Activity

Herein, we report cellulose-based threads from Indian sacred Lotus (Nelumbo nucifera) of the Nymphaceae family embellished with MoS2 nanosheets for its enhanced hydrophobic and antimicrobial properties. MoS2 nanosheets synthesized by a coprecipitation method using sodium molybdate dihydrate (Na2MoO4·2H2O) and thioacetamide (CH3CSNH2) were used as a sourse for MoS2 particle growth with cellulose threads extracted from lotus peduncles. The size, crystallinity, and morphology of pure and MoS2-coated fibers were studied using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). the XRD pattern of pure lotus threads showed a semicrystalline nature, and the threads@MoS2 composite showed more crystallinity than the pure threads. SEM depicts that pure lotus threads possess a smooth surface, and the MoS2 nanosheets growth can be easily identified on the threads@MoS2. Further, the presence of MoS2 nanosheets on threads was confirmed with EDX elemental analysis. Antimicrobial studies with Escherichia coli and Candida albicans reveal that threads@MoS2 have better resistance than its counterpart, i.e., pure threads. MoS2 sheets play a predominant role in restricting the wicking capability of the pure threads due to their enhanced hydrophobic property. The water absorbency assay denotes the absorption rate of threads@MoS2 to 80%, and threads@MoS2 shows no penetration for the observed 60 min, thus confirming its wicking restriction. The contact angle for threads@MoS2 is 128°, indicating its improved hydrophobicity.

Self-assembled NIR-responsive MoS2@quaternized chitosan/nanocellulose composite paper for recyclable antibacteria

Paper products are widely used in daily life, while the lack of antibacterial activity has made them become some disease transmission media. Herein, we introduced NIR-responsive molybdenum disulfide nanosheets (MoS₂) to endow nanocellulose paper antibacterial activity by electrostatic self-assembly with quaternized chitosan (QCS). Firstly, the MoS₂ nanosheets were exfoliated and stabilized with QCS under ultrasonication. The strong coordination between QCS and MoS₂ as well as the electrostatic attraction between QCS and cellulose nanofiber (CNF) helped to fabricate the MoS₂@QCS/CNF composite paper. The MoS₂@QCS/CNF composite paper exhibited excellent photothermal and photodynamic activity, achieving over 99.9% antibacterial efficacy against both E. coli and S. aureus, respectively. The hyperthermia induced by MoS₂ accelerated the glutathione (GSH) consumption and the reactive oxygen species (ROS)-independent oxidative stress destroyed the bacteria membranes integrity, synergistically leading to the malondialdehyde (MDA) oxidation and protein leakage to inhibit the bacteria growth. Importantly, the self-assembled fibrous network incorporating with the photo-stable antibacterial MoS₂ enabled the flexible composite paper with excellent mechanical strength and recyclability for long-term antimicrobial, possessing over 99.9% inhibition even after five cycles. No cell cytotoxicity was observed for the MoS₂@QCS/CNF composite paper, suggesting the potential of composite paper for bacterial infection control.

Functionalization of 2D MoS2 Nanosheets with Various Metal and Metal Oxide Nanostructures: Their Properties and Application in Electrochemical Sensors

Two-dimensional transition metal dichalcogenides (2D TMDs) have gained considerable attention due to their distinctive properties and broad range of possible applications. One of the most widely studied transition metal dichalcogenides is molybdenum disulfide (MoS₂). The 2D MoS₂ nanosheets have unique and complementary properties to those of graphene, rendering them ideal electrode materials that could potentially lead to significant benefits in many electrochemical applications. These properties include tunable bandgaps, large surface areas, relatively high electron mobilities, and good optical and catalytic characteristics. Although the use of 2D MoS₂ nanosheets offers several advantages and excellent properties, surface functionalization of 2D MoS₂ is a potential route for further enhancing their properties and adding extra functionalities to the surface of the fabricated sensor. The functionalization of the material with various metal and metal oxide nanostructures has a significant impact on its overall electrochemical performance, improving various sensing parameters, such as selectivity, sensitivity, and stability. In this review, different methods of preparing 2D-layered MoS₂ nanomaterials, followed by different surface functionalization methods of these nanomaterials, are explored and discussed. Finally, the structure-properties relationship and electrochemical sensor applications over the last ten years are discussed. Emphasis is placed on the performance of 2D MoS₂ with respect to the performance of electrochemical sensors, thereby giving new insights into this unique material and providing a foundation for researchers of different disciplines who are interested in advancing the development of MoS₂-based sensors.

Graphene-MoS2 polyfunctional hybrid hydrogels for the healing of transected Achilles tendon

Healing of injured tendon is a major clinical challenge in orthopaedic medicine, due to the poor regenerative potential of this tissue. Two-dimensional nanomaterials, as versatile scaffolds, have shown a great potential to support, trigger and accelerate the tendon regeneration. However, weak mechanical properties, poor functionality and low biocompatibility of these scaffolds as well as post-surgery infections are main drawbacks that limit their development in the higher clinical phases. In this work, a series of hydrogels consisting polyglycerol functionalized reduced graphene oxide (PG), polyglycerol-functionalized molybdenum disulfide (PMoS₂) and PG/PMoS₂ hybrid within the gelatin matrix are formulated in new scaffolds and their ability for the healing of injured Achilles tendon, due to their high mechanical properties, low toxicity, cell proliferation enhancement, and antibacterial activities is investigated. While scaffolds containing PG and PMoS₂ showed a moderate tendon regeneration and anti-inflammatory effect, respectively, their hybridization into PG/PMoS₂ demonstrated a synergistic healing efficiency. Along the same line, an accelerated return of tendon function with low peritendinous adhesion and low cross-sectional area in animal group treated with scaffold containing PG/PMoS₂ was observed. Taking advantage of the high biocompatibility, high strength, straightforward construction and fast tendon regeneration, PG/PMoS₂ can be used as a new scaffold for the future tissue engineering.

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.

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.

2D Molybdenum Sulfide-Based Materials for Photo-Excited Antibacterial Application

Bacterial infections have seriously threatened human health and the abuse of natural or artificial antibiotics leads to bacterial resistance, so development of a new generation of antibacterial agents and treatment methods is urgent. 2D molybdenum sulfide (MoS₂ ) has good biocompatibility, high specific surface area to facilitate surface modification and drug loading, adjustable energy bandgap, and high near-infrared photothermal conversion efficiency (PCE), so it is often used for antibacterial application through its photothermal or photodynamic effects. This review comprehensively summarizes and discusses the fabrication processes, structural characteristics, antibacterial performance, and the corresponding mechanisms of MoS₂ -based materials as well as their representative antibacterial applications. In addition, the outlooks on the remaining challenges that should be addressed in the field of MoS₂ are also proposed.

Molybdenum disulfide (MoS2)-based nanostructures for tissue engineering applications: prospects and challenges

Molybdenum disulfide (MoS₂) nanostructures have recently earned substantial thoughts from the scientific communities owing to their unique physicochemical, optical and electrical properties. Although MoS₂ has been mostly highlighted for its industrial applications, its biological applicability has not been extensively explored. The introduction of nanotechnology in the field of tissue engineering has significantly contributed to human welfare by displaying advancement in tissue regeneration. Assimilation of MoS₂ nanostructures into the polymer matrix has been considered a persuasive material of choice for futuristic tissue engineering applications. The current review provides a general discussion on the structural properties of different MoS₂ nanostructures. Further, this article focuses on the interactions of MoS₂ with biological systems in terms of its cellular toxicity, and biocompatibility along with its capability for cell proliferation, adhesion, and immunomodulation. The article continues to confer the utility of MoS₂ nanostructure-based scaffolds for various tissue engineering applications. The article also highlights some emerging prospects and possibilities of the applicability of MoS₂-based nanostructures in large organ tissue engineering. Finally, the article concludes with a brief annotation on the challenges and limitations that need to be overcome in order to make plentiful use of this wonderful material for tissue engineering applications.

An erythrocyte membrance-camouflaged biomimetic nanoplatform for enhanced chemo-photothermal therapy of breast cancer

Nano drug delivery system is a research hotspot in the field of tumor therapy. Molybdenum disulfide (MoS2) nanosheet was selected as the base material and natural red blood cell membrane...

Sulfonic acid/sulfur trioxide (SO3H/SO3) functionalized two-dimensional MoS2 nanosheets for high-performance photocatalysis of organic pollutants

We report the enhanced photocatalytic activity of sulfonic acid/sulfur trioxide (SO3H/SO3) functionalized two-dimensional (2D)-MoS2 (SO3H/SO3-MoS2) nanosheets synthesized using a one-pot hydrothermal method.