Biological interactions of biocompatible and water-dispersed MoS2 nanosheets with bacteria and human cells

Knot Architecture for Biocompatible and Semiconducting 2D Electronic Fiber Transistors

Wearable devices have generally been rigid due to their reliance on silicon-based technologies, while future wearables will utilize flexible components for example transistors within microprocessors to manage data. Two-dimensional (2D) semiconducting flakes have yet to be investigated in fiber transistors but can offer a route toward high-mobility, biocompatible, and flexible fiber-based devices. Here, the electrochemical exfoliation of semiconducting 2D flakes of tungsten diselenide (WSe2) and molybdenum disulfide (MoS2) is shown to achieve homogeneous coatings onto the surface of polyester fibers. The high aspect ratio (>100) of the flake yields aligned and conformal flake-to-flake junctions on polyester fibers enabling transistors with mobilities μ ≈1 cm2 V-1 s-1 and a current on/off ratio, Ion/Ioff ≈102-104. Furthermore, the cytotoxic effects of the MoS2 and WSe2 flakes with human keratinocyte cells are investigated and found to be biocompatible. As an additional step, a unique transistor 'knot' architecture is created by leveraging the fiber diameter to establish the length of the transistor channel, facilitating a route to scale down transistor channel dimensions (≈100 µm) and utilize it to make a MoS2 fiber transistor with a human hair that achieves mobilities as high as μ ≈15 cm2 V-1 s-1.

Investigation of oral toxicity of WS2 nanosheets to mouse intestine: Pathological injury, trace element balance, lipid profile changes, and autophagy

The success of graphene oxides has gained extensive research interests in developing novel 2D nanomaterials (NMs). WS2 nanosheets (NSs) are novel transition metal-based 2D NMs, but their toxicity is unclear. In this study, we investigated the oral toxicity of WS2 NSs to mouse intestines. Male mice were administrated with vehicles, 1, 10, or 100 mg/kg NSs via intragastric route, once a day, for 5 days. The results indicate that the NSs did not induce pathological or ultrastructural changes in intestines. There were minimal changes of trace elements that the exposure did not induce W accumulation, and only Co levels were dose-dependently increased. Lipid droplets were observed in all groups of mice, but lipidomics data indicate that WS2 NSs only significantly decreased four lipid species, all belonging to phosphatidylcholine (PC). The levels of proteins regulating autophagic lipolysis, namely, LC3, lysosomal associated membrane protein 2 (LAMP2) and perilipin 2 (PLIN2), were increased, but it was only statistically significantly different for LC3. The results of this study suggest that repeated intragastric exposure to WS2 NSs only induced minimal influences on pathological injury, trace element balance, autophagy, and lipid profiles in mouse intestines, indicating relatively high biocompatibility of WS2 NSs to mouse intestine via oral route.

Gamma rays impact on 2D-MoS2 in water solution

Two-dimensional transition metal dichalcogenides, particularly MoS2, are interesting materials for many applications in aerospace research, radiation therapy and bioscience more in general. Since in many of these applications MoS2-based nanomaterials can be placed in an aqueous environment while exposed to ionizing radiation, both experimental and theoretical studies of their behaviour under these conditions is particularly interesting. Here, we study the effects of tiny imparted doses of 511 keV photons to MoS2 nanoflakes in water solution. To the best of our knowledge, this is the first study in which ionizing radiation on 2D-MoS2 occurs in water. Interestingly, we find that, in addition to the direct interaction between high-energy photons and nanoflakes, reactive chemical species, generated by γ-photons induced radiolysis of water, come into play a relevant role. A radiation transport Monte Carlo simulation allowed determining the elements driving the morphological and spectroscopical changes of 2D-MoS2, experimentally monitored by SEM microscopy, DLS, Raman and UV-vis spectroscopy, AFM, and X-ray photoelectron techniques. Our study demonstrates that radiolysis products affect the Molybdenum oxidation state, which is massively changed from the stable + 4 and + 6 states into the rarer and more unstable + 5. These findings will be relevant for radiation-based therapies and diagnostics in patients that are assuming drugs or contrast agents containing 2D-MoS2 and for aerospace biomedical applications of 2DMs investigating their actions into living organisms on space station or satellites.

Exploring bio-nanomaterials as antibiotic allies to combat antimicrobial resistance

Antimicrobial resistance (AMR) poses an emergent threat to global health due to antibiotic abuse, overuse and misuse, necessitating urgent innovative and sustainable solutions. The utilization of bio-nanomaterials as antibiotic allies is a green, economic, sustainable and renewable strategy to combat this pressing issue. These biomaterials involve green precursors (e.g. biowaste, plant extracts, essential oil, microbes, and agricultural residue) and techniques for their fabrication, which reduce their cyto/environmental toxicity and exhibit economic manufacturing, enabling a waste-to-wealth circular economy module. Their nanoscale dimensions with augmented biocompatibility characterize bio-nanomaterials and offer distinctive advantages in addressing AMR. Their ability to target pathogens, such as bacteria and viruses, at the molecular level, coupled with their diverse functionalities and bio-functionality doping from natural precursors, allows for a multifaceted approach to combat resistance. Furthermore, bio-nanomaterials can be tailored to enhance the efficacy of existing antimicrobial agents or deliver novel therapies, presenting a versatile platform for innovation. Their use in combination with traditional antibiotics can mitigate resistance mechanisms, prolong the effectiveness of existing treatments, and reduce side effects. This review aims to shed light on the potential of bio-nanomaterials in countering AMR, related mechanisms, and their applications in various domains. These roles encompass co-therapy, nanoencapsulation, and antimicrobial stewardship, each offering a distinct avenue for overcoming AMR. Besides, it addresses the challenges associated with bio-nanomaterials, emphasizing the importance of regulatory considerations. These green biomaterials are the near future of One Health Care, which will have economic, non-polluting, non-toxic, anti-resistant, biocompatible, degradable, and repurposable avenues, contributing to sustainable development goals.

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.

Improvement photothermal property of MoS2/Fe3O4/GNR nanocomposite in cancer treatment

The objective of the present study was to develop a novel molybdenum disulfide/iron oxide/gold nanorods (MoS2/Fe3O4/GNR) nanocomposite (MFG) with different concentrations of AgNO3 solution (MFG1, MFG2, and MFG3) for topical doxorubicin (DOX) drug delivery. Then, these nanocomposites were synthesized and characterized by Fourier transform infrared (FTIR), Transmission electron microscopy (TEM), Dynamic light scattering (DLS), and Ultraviolet-visible (UV-Vis) spectroscopies to confirm their structural and optical properties. Cytotoxicity of samples on Hela cell was determined using MTT assay. Results indicated that nanocomposites possess little cytotoxicity without NIR laser irradiation. Also, the relative viabilities of Hela cells decreased when the concentration of AgNO3 solution increased in this nanocomposite. Using NIR irradiation, the relative viabilities of Hela cells decreased when the concentration of samples increased. Acridine orange/propidium iodide (PI) staining, flow cytometry were recruited to evaluate the effect of these nanocomposites on apoptosis of Hela cells. Finally, results revealed when DOX loading increased in nanocomposite, then cell viability was decreased in it. Therefore, these properties make MFG3 nanocomposite a good candidate for photothermal therapy and drug loading.

Biocompatible 2D Materials via Liquid Phase Exfoliation

2D materials (2DMs), such as graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BP), have been proposed for different types of bioapplications, owing to their unique physicochemical, electrical, optical, and mechanical properties. Liquid phase exfoliation (LPE), as one of the most effective up-scalable and size-controllable methods, is becoming the standard process to produce high quantities of various 2DM types as it can benefit from the use of green and biocompatible conditions. The resulting exfoliated layered materials have garnered significant attention because of their biocompatibility and their potential use in biomedicine as new multimodal therapeutics, antimicrobials, and biosensors. This review focuses on the production of LPE-assisted 2DMs in aqueous solutions with or without the aid of surfactants, bioactive, or non-natural molecules, providing insights into the possibilities of applications of such materials in the biological and biomedical fields.

From Bulk Molybdenum Disulfide (MoS2) to Suspensions of Exfoliated MoS2 in an Aqueous Medium and Their Applications

Two-dimensional (2D) layered materials like graphene, transition-metal dichalcogenides (TMDs), boron nitrides, etc., exhibit unique and fascinating properties, such as high surface-to-volume ratio, inherent mechanical flexibility and robustness, tunable bandgap, and high carrier mobility, which makes them an apt candidate for flexible electronics with low consumption of power. Because of these properties, they are in tremendous demand for advancement in energy, environmental, and biomedical sectors developed through various technologies. The production and scalability of these materials must be sustainable and ecofriendly to utilize these unique properties in the real world. Here, in this current review, we review molybdenum disulfide (MoS2 nanosheets) in detail, focusing on exfoliated MoS2 in water and the applicability of aqueous MoS2 suspensions in various fields. The exfoliation of MoS2 results in the formation of single or few-layered MoS2. Therefore, this Review focuses on the few layers of exfoliated MoS2 that have the additional properties of 2D layered materials and higher excellent compatibility for integration than existing conventional Si tools. Hence, a few layers of exfoliated MoS2 are widely explored in biosensing, gas sensing, catalysis, photodetectors, energy storage devices, a light-emitting diode (LED), adsorption, etc. This review covers the numerous methodologies to exfoliate MoS2, focusing on the various published methodologies to obtain nanosheets of MoS2 from water solutions and their use.

Broadening spectral responses and achieving environmental stability in SnS2/Ag-NPs/HfO2 flexible phototransistors

Layered two-dimensional (2D) materials have gained popularity thanks to their atomically thin physique and strong coupling with light. Here, we investigated a wide band gap (≥ 2 eV) 2D material, i.e., tin disulfide (SnS2), and decorated it with silver nanoparticles, Ag-NPs, for broadband photodetection. Our results show that the SnS2/Ag-NPs devices exhibit broadband photodetection ranging from the ultraviolet to near-infrared (250-1050 nm) spectrum with decreased rise/decay times from 8/20 s to 7/16 s under 250 nm wavelength light compared to the bare SnS2 device. This is attributed to the localized surface plasmon resonance effect and the wide band gap of SnS2 crystal. Furthermore, the HfO2-passivated SnS2/Ag-NPs devices exhibited high photodetection performance in terms of photoresponsivity (∼12 500 A W-1), and external quantum efficiency (∼6 × 106%), which are significantly higher compared to those of bare SnS2. Importantly, after HfO2 passivation, the SnS2/Ag-NPs photodetector maintained the stable performance for several weeks with merely ∼5.7% reduction in photoresponsivity. Lastly, we fabricated a flexible SnS2/Ag-NPs photodetector, which shows excellent and stable performance under various bending curvatures (0, 20, and 10 mm), as it retains ∼80% of its photoresponsivity up to 500 bending cycles. Thus, our study provides a simple route to realize broadband and stable photoactivity in flexible 2D material-based devices.

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.

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.

Synthesis, Characterisation, and Functionalisation of Charged Two-Dimensional MoS2

The applications of exfoliated MoS2 are limited by its inert surface and poor interface. We have activated the surface of exfoliated 2H-MoS2 by reacting it with NaBH4 , forming an n-doped material as demonstrated by a negative zeta-potential value ζ=-25 mV and a 20 nm (0.05 eV) red-shift in its photoluminescence spectrum. The novel material's spectral properties were consistent with pristine 2H-MoS2 (as determined by HR-TEM, XPS, pXRD, DRIFT, TGA, and Raman spectroscopy). Importantly, it was readily dispersed in H2 O unlike 2H-MoS2 . Its dispersibility properties were explored for a variety of solvents and could be directly correlated with the relative permittivity of the respective solvents. The charged 2H-MoS2 reacted readily with an organo-iodide to deliver functionalized 2H-MoS2 . Our approach delivers aqueous dispersions of semiconducting 2H-MoS2 , without additives or chemical functionalities, and allows for controlled and facile functionalization of 2H-MoS2 opening multiple new avenues of semi-conducting MoS2 application.

Photothermal therapy using graphene quantum dots

The rapid development of powerful anti-oncology medicines have been possible because of advances in nanomedicine. Photothermal therapy (PTT) is a type of treatment wherein nanomaterials absorb the laser energy and convert it into localized heat, thereby causing apoptosis and tumor eradication. PTT is more precise, less hazardous, and easy-to-control in comparison to other interventions such as chemotherapy, photodynamic therapy, and radiation therapy. Over the past decade, various nanomaterials for PTT applications have been reviewed; however, a comprehensive study of graphene quantum dots (GQDs) has been scantly reported. GQDs have received huge attention in healthcare technologies owing to their various excellent properties, such as high water solubility, chemical stability, good biocompatibility, and low toxicity. Motivated by the fascinating scientific discoveries and promising contributions of GQDs to the field of biomedicine, we present a comprehensive overview of recent progress in GQDs for PTT. This review summarizes the properties and synthesis strategies of GQDs including top-down and bottom-up approaches followed by their applications in PTT (alone and in combination with other treatment modalities such as chemotherapy, photodynamic therapy, immunotherapy, and radiotherapy). Furthermore, we also focus on the systematic study of in vitro and in vivo toxicities of GQDs triggered by PTT. Moreover, an overview of PTT along with the synergetic application used with GQDs for tumor eradication are discussed in detail. Finally, directions, possibilities, and limitations are described to encourage more research, which will lead to new treatments and better health care and bring people closer to the peak of human well-being.

Molybdenum Disulfide as Tunable Electrochemical and Optical Biosensing Platforms for Cancer Biomarker Detection: A Review

Cancer is a common illness with a high mortality. Compared with traditional technologies, biomarker detection, with its low cost and simple operation, has a higher sensitivity and faster speed in the early screening and prognosis of cancer. Therefore, extensive research has focused on the development of biosensors and the construction of sensing interfaces. Molybdenum disulfide (MoS2) is a promising two-dimensional (2D) nanomaterial, whose unique adjustable bandgap shows excellent electronic and optical properties in the construction of biosensor interfaces. It not only has the advantages of a high catalytic activity and low manufacturing costs, but it can also further expand the application of hybrid structures through different functionalization, and it is widely used in various biosensors fields. Herein, we provide a detailed introduction to the structure and synthesis methods of MoS2, and explore the unique properties and advantages/disadvantages exhibited by different structures. Specifically, we focus on the excellent properties and application performance of MoS2 and its composite structures, and discuss the widespread application of MoS2 in cancer biomarkers detection from both electrochemical and optical dimensions. Additionally, with the cross development of emerging technologies, we have also expanded the application of other emerging sensors based on MoS2 for early cancer diagnosis. Finally, we summarized the challenges and prospects of MoS2 in the synthesis, functionalization of composite groups, and applications, and provided some insights into the potential applications of these emerging nanomaterials in a wider range of fields.

The Effectiveness of Cyrene as a Solvent in Exfoliating 2D TMDs Nanosheets

The pursuit of environmentally friendly solvents has become an essential research topic in sustainable chemistry and nanomaterial science. With the need to substitute toxic solvents in nanofabrication processes becoming more pressing, the search for alternative solvents has taken on a crucial role in this field. Additionally, the use of toxic, non-economical organic solvents, such as N-methyl-2 pyrrolidone and dimethylformamide, is not suitable for all biomedical applications, even though these solvents are often considered as the best exfoliating agents for nanomaterial fabrication. In this context, the success of producing two-dimensional transition metal dichalcogenides (2D TMDs), such as MoS₂ and WS₂, with excellent captivating properties is due to the ease of synthesis based on environment-friendly, benign methods with fewer toxic chemicals involved. Herein, we report for the first time on the use of cyrene as an exfoliating agent to fabricate monolayer and few-layered 2D TMDs with a versatile, less time-consuming liquid-phase exfoliation technique. This bio-derived, aprotic, green and eco-friendly solvent produced a stable, surfactant-free, concentrated 2D TMD dispersion with very interesting features, as characterized by UV-visible and Raman spectroscopies. The surface charge and morphology of the fabricated nanoflakes were analyzed using ς-potential and scanning electron microscopy. The study demonstrates that cyrene is a promising green solvent for the exfoliation of 2D TMD nanosheets with potential advantages over traditional organic solvents. The ability to produce smaller-sized-especially in the case of WS₂ as compared to MoS₂-and mono/few-layered nanostructures with higher negative surface charge values makes cyrene a promising candidate for various biomedical and electronic applications. Overall, the study contributes to the development of sustainable and environmentally friendly methods for the production of 2D nanomaterials for various applications.

Dual-Mode Fluorescence/Ultrasound Imaging with Biocompatible Metal-Doped Graphene Quantum Dots

Sonography offers many advantages over standard methods of diagnostic imaging due to its non-invasiveness, substantial tissue penetration depth, and low cost. The benefits of ultrasound imaging call for the development of ultrasound-trackable drug delivery vehicles that can address a variety of therapeutic targets. One disadvantage of the technique is the lack of high-precision imaging, which can be circumvented by complementing ultrasound contrast agents with visible and, especially, near-infrared (NIR) fluorophores. In this work, we, for the first time, develop a variety of lightly metal-doped (iron oxide, silver, thulium, neodymium, cerium oxide, cerium chloride, and molybdenum disulfide) nitrogen-containing graphene quantum dots (NGQDs) that demonstrate high-contrast properties in the ultrasound brightness mode and exhibit visible and/or near-infrared fluorescence imaging capabilities. NGQDs synthesized from glucosamine precursors with only a few percent metal doping do not introduce additional toxicity in vitro, yielding over 80% cell viability up to 2 mg/mL doses. Their small (<50 nm) sizes warrant effective cell internalization, while oxygen-containing surface functional groups decorating their surfaces render NGQDs water soluble and allow for the attachment of therapeutics and targeting agents. Utilizing visible and/or NIR fluorescence, we demonstrate that metal-doped NGQDs experience maximum accumulation within the HEK-293 cells 6-12 h after treatment. The successful 10-fold ultrasound signal enhancement is observed at 0.5-1.6 mg/mL for most metal-doped NGQDs in the vascular phantom, agarose gel, and animal tissue. A combination of non-invasive ultrasound imaging with capabilities of high-precision fluorescence tracking makes these metal-doped NGQDs a viable agent for a variety of theragnostic applications.

Superparamagnetic Nickel Nanocluster-Embedded MoS2 Nanosheets for Gram-Selective Bacterial Adhesion and Antibacterial Activity

Ever increasing infectious diseases caused by pathogenic bacteria are creating one of the greatest health problems. The extensive use of numerous antibiotics and antimicrobial agents has prompted the growth of multidrug-resistant bacterial strains. The ancient biomedical application of metals and the recent advancement in the field of nanotechnology have encouraged us to explore the antimicrobial activity of nanomaterials. Herein, we have synthesized a magnetically separable superparamagnetic nickel nanocluster-loaded two-dimensional molybdenum disulfide nanocomposite (Ni@2D-MoS₂). It can selectively bind with Gram-positive bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis over Gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. After the functionalization of Ni@2D-MoS₂ with a positively charged ligand, it showed an excellent Gram-selective antibacterial activity toward MRSA and E. faecalis. Furthermore, the superparamagnetic property of the synthesized material can be used for the simultaneous removal and killing of the microbes and recycled for further use. This study demonstrates strategies to develop hybrid antimicrobial nanomaterial systems for selective antibacterial activity with recyclability.

Polarization-Dependent Sum-Frequency Generation Spectroscopy for Ångstrom-Scale Depth Profiling of Molecules at Interfaces

The three-dimensional spatial distribution of molecules at soft matter interfaces is crucial for processes ranging from membrane biophysics to atmospheric chemistry. While several techniques can access surface composition, obtaining information on the depth distribution is challenging. We develop a noninvasive, polarization-resolved, surface-specific sum-frequency generation spectroscopy providing quantitative depth information. We demonstrate the technique on formic acid molecules at the air-water interface. With increasing molar fraction from 2.5% to 10%, the formic acid molecules shift, on average, ∼0.9  Å into the bulk. The consistency with the simulation data manifests that the technique allows for probing the Ångstrom-scale depth profile.

Enhanced Catalytic Activity of a New Nanobiocatalytic System Formed by the Adsorption of Cytochrome c on Pluronic Triblock Copolymer Stabilized MoS2 Nanosheets

The formation of nanobiohybrids through the immobilization of enzymes on functional nanomaterials has opened up exciting research opportunities at the nanobiointerfaces. These systems hold great promise for a wide range of applications in biosensing, biocatalytic, and biomedical fields. Here, we report the formation of a hybrid nanobiocatalytic system through the adsorption of cytochrome c (Cyt c) on pluronic triblock copolymer, P123 (PEO-b-PPO-b-PEO), stabilized MoS2 nanosheets. The use of pluronic polymer has helped not only to greatly stabilize the exfoliated MoS2 nanosheets but also to allow easy adsorption of Cyt c on the nanosheets without major structural changes due to its excellent biocompatibility and soft protein-binding property. By comparing the catalytic activity of the Cyt c-MoS2 nanobiohybrid with that of the free Cyt c and as-prepared MoS2 nanosheets, we have demonstrated the active role of the nanobiointeractions in enhancing the catalytic activity of the hybrid. Slight structural perturbation at the active site of the Cyt c upon adsorption on MoS2 has primarily facilitated the peroxidase activity of the Cyt c. As the MoS2 nanosheets and the native Cyt c individually exhibit weaker intrinsic peroxidase activities, their mutual modulation at the nanobiointerface has made the Cyt c-MoS2 a novel nanobiocatalyst with superior activity.

Spontaneous formation of gold nanoparticles on MoS2 nanosheets and its impact on solution-processed optoelectronic devices

Understanding size-dependent properties of 2D materials is crucial for their optimized performance when incorporated through solution routes. In this work, the chemical nature of MoS₂ as a function of nanosheet size is investigated through the spontaneous reduction of chloroauric acid. Microscopy studies suggest higher gold nanoparticle decoration density in smaller nanosheet sizes, resulting from higher extent of reduction. Further corroboration through surface-enhanced Raman scattering using the gold-decorated MoS₂ nanosheets as substrates exhibited an enhancement factor of 1.55 × 10⁶ for smaller nanosheets which is 7-fold higher as compared to larger nanosheets. These plasmonic-semiconductor hybrids are utilized for photodetection, where decoration is found to impact the photoresponse of smaller nanosheets the most, and is optimized to achieve responsivity of 367.5 mAW^-1 and response times of ∼17 ms. The simplistic modification via solution routes and its impact on optoelectronic properties provides an enabling platform for 2D materials-based applications.

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Reducing agent-free Au nanoparticle decoration on aqueously dispersed 2H-MoS₂.

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Control on Au nanoparticle decoration density through nanosheet size-selection.

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SERS as a probe for determining the decoration density along with microscopy.

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Enhanced photodetection by spontaneous modification with Au on MoS₂ films.

Single-Cell Photothermal Analysis Induced by MoS2 Nanoparticles by Raman Spectroscopy

Two-dimensional nanomaterials, such as MoS2 nanosheets, have been attracting increasing attention in cancer diagnosis and treatment, thanks to their peculiar physical and chemical properties. Although the mechanisms which regulate the interaction between these nanomaterials and cells are not yet completely understood, many studies have proved their efficient use in the photothermal treatment of cancer, and the response to MoS2 nanosheets at the single-cell level is less investigated. Clearly, this information can help in shedding light on the subtle cellular mechanisms ruling the interaction of this 2D material with cells and, eventually, to its cytotoxicity. In this study, we use confocal micro-Raman spectroscopy to reconstruct the thermal map of single cells targeted with MoS2 under continuous laser irradiation. The experiment is performed by analyzing the water O-H stretching band around 3,400 cm−1 whose tetrahedral structure is sensitive to the molecular environment and temperature. Compared to fluorescence-based approaches, this Raman-based strategy for temperature measurement does not suffer fluorophore instability, which can be significant under continuous laser irradiation. We demonstrate that irradiation of human breast cancer MCF7 cells targeted with MoS2 nanosheets causes a relevant photothermal effect, which is particularly high in the presence of MoS2 nanosheet aggregates. Laser-induced heating is strongly localized near such particles which, in turn, tend to accumulate near the cytoplasmic membrane. Globally, our experimental outcomes are expected to be important for tuning the nanosheet fabrication process.

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.

Synthesis and Photoluminescence Properties of MoS2/Graphene Heterostructure by Liquid-Phase Exfoliation

Here, we report the synthesis of MoS2/graphene heterostructure in single-stage, liquid-phase exfoliation using a 7:3 isopropyl alcohol/water mixture. Further, the synthesized heterostructure was characterized using UV-visible and micro-Raman spectroscopies, transmission electron microscopy (TEM), and dynamic light scattering (DLS) analysis. UV-visible and micro-Raman analyses confirmed that the synthesized heterostructure had mostly few-layered (two-to-four sheets) MoS2. The photophysical properties of the heterostructure were analyzed using steady-state and time-resolved luminescence techniques. Enhanced photoluminescence was observed in the case of the heterostructure probably due to an increase in the defect sites or reduction in the rate of nonradiative decay upon formation of the sandwiched heterostructure. Applications of this heterostructure for fluorescence live-cell imaging were carried out, and the heterostructure demonstrated a better luminescence contrast compared to its individual counterpart MoS2 in phosphate-buffered saline (PBS).

Fabrication of eco-friendly chitosan functionalized few-layered WS2 nanocomposite implanted with ruthenium nanoparticles for in vitro antibacterial and anticancer activity: Synthesis, characterization, and pharmaceutical applications

The abundance of two-dimensional (2D) components has provided them with a broad material platform for building nano and atomic-level applications. So, 2D nanomaterials are unique because of their physicochemical properties. Over many years, graphene is a conventional 2D layered element that has significant attention in the scientific community. In recent years numerous new 2D nanomaterials other than graphene have been reported. The study of 2D nanomaterials is also in its infant stages, with the majority of research focusing on the explanation of special material properties, but very few articles are focusing on the biological applications of 2D nanomaterials. As a result, we focused on the transition metal dichalcogenides (TMDCs) such as MoS₂ and WS₂, which were emerging and exciting groups of elements with display great opportunities in several fields, such as cancer nanomedicine. Herein, we synthesized biologically active CS/WS₂/Ru composite by liquid exfoliation approach. The CS/WS₂/Ru composites exhibit significant antibacterial action towards (S. aureus, and E. coli) bacteria. Also, the composite suggests synergetic anticancer action against MCF-7 cancer cells. These reports are possible to explore the innovative aspects of biological outcomes in carcinological applications.

Effects of MoS2 Layer Thickness on Its Photochemically Driven Oxidative Dissolution

The distinctive optical and electronic properties of two-dimensional (2D) molybdenum disulfide (MoS₂) make it a promising photocatalyst and photothermal agent in aqueous applications. In terms of environmental stability, MoS₂ has been considered insoluble, but 2D MoS₂ nanosheets can be susceptible to dissolution, owing to their large surface areas and highly accessible reactive sites, including defects at the basal plane and edge sites. Under light illumination, the dissolution of 2D MoS₂ nanosheets can be further accelerated by their photochemical reactivity. To elucidate MoS₂ reactivity in the environment, here we investigated the thickness-dependent dissolution of MoS₂ under illumination. To synthesize nanoscale thicknesses of MoS₂, we exfoliated bulk MoS₂ by ultrasonication and controlled the layer thickness by iterative cascade centrifugation, producing MoS₂ nanosheets averaging either ∼18 nm or ∼46 nm thick, depending on the centrifugation rate. Under simulated sunlight, MoS₂ dissolution was accelerated, the Mo⁶⁺ composition increased, and the solution pH decreased compared to those in the dark. These results suggest that light exposure promotes the oxidation of MoS₂, causing faster dissolution. Importantly, 18 nm thick MoS₂ exhibited faster dissolution than either 46 nm or bulk MoS₂, driven by the superoxide radical (O₂^•-) generation promoted by its relative thinness. These findings highlight the important role of the thickness-dependent photochemistry of MoS₂ nanosheets in their dissolution, which is directly linked to their environmental behavior and stability.

Hydrothermal green synthesis of MoS2 nanosheets for pollution abatement and antifungal applications

In this study, we report a green synthesis of MoS₂ nanosheets (NSs) using a facile hydrothermal technique in the presence of l-cysteine. l-Cysteine can serve as a greener source of sulfur as well as a capping agent to help the growth of MoS₂ nanosheets. The prepared materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), electron transmission microscopy (TEM), X-ray photoelectron microscopy (XPS), and Brunauer, Emmett, and Teller (BET) analysis. The results showed that MoS₂ NSs are of high crystallinity with a lattice spacing of 0.61 nm. The optical bandgap of MoS₂ NSs nanosheets prepared using l-cysteine as a source of sulfur was found to be 1.79 eV. The photocatalytic degradation of MoS₂ NSs towards methylene orange (MO) and rhodamine blue (RB) dyes under sunlight was found to be promising for practical applications. The fast kinetics of degradation of MO and RhB was observed over a wide range of pH range. Moreover, MoS₂ NSs showed excellent antifungal activities against Trichophyton mentagrophytes and Penicillium chrysogenum fungus.

Antipathogenic properties and applications of low-dimensional materials

A major health concern of the 21st century is the rise of multi-drug resistant pathogenic microbial species. Recent technological advancements have led to considerable opportunities for low-dimensional materials (LDMs) as potential next-generation antimicrobials. LDMs have demonstrated antimicrobial behaviour towards a variety of pathogenic bacterial and fungal cells, due to their unique physicochemical properties. This review provides a critical assessment of current LDMs that have exhibited antimicrobial behaviour and their mechanism of action. Future design considerations and constraints in deploying LDMs for antimicrobial applications are discussed. It is envisioned that this review will guide future design parameters for LDM-based antimicrobial applications.

Nanotoxicity of 2D Molybdenum Disulfide, MoS2, Nanosheets on Beneficial Soil Bacteria, Bacillus cereus and Pseudomonas aeruginosa

Concerns arising from accidental and occasional releases of novel industrial nanomaterials to the environment and waterbodies are rapidly increasing as the production and utilization levels of nanomaterials increase every day. In particular, two-dimensional nanosheets are one of the most significant emerging classes of nanomaterials used or considered for use in numerous applications and devices. This study deals with the interactions between 2D molybdenum disulfide (MoS2) nanosheets and beneficial soil bacteria. It was found that the log-reduction in the survival of Gram-positive Bacillus cereus was 2.8 (99.83%) and 4.9 (99.9988%) upon exposure to 16.0 mg/mL bulk MoS2 (macroscale) and 2D MoS2 nanosheets (nanoscale), respectively. For the case of Gram-negative Pseudomonas aeruginosa, the log-reduction values in bacterial survival were 1.9 (98.60%) and 5.4 (99.9996%) for the same concentration of bulk MoS2 and MoS2 nanosheets, respectively. Based on these findings, it is important to consider the potential toxicity of MoS2 nanosheets on beneficial soil bacteria responsible for nitrate reduction and nitrogen fixation, soil formation, decomposition of dead and decayed natural materials, and transformation of toxic compounds into nontoxic compounds to adequately assess the environmental impact of 2D nanosheets and nanomaterials.

A Review on MoS2 Properties, Synthesis, Sensing Applications and Challenges

Molybdenum disulfide (MoS2) is one of the compounds discussed nowadays due to its outstanding properties that allowed its usage in different applications. Its band gap and its distinctive structure make it a promising material to substitute graphene and other semiconductor devices. It has different applications in electronics especially sensors like optical sensors, biosensors, electrochemical biosensors that play an important role in the detection of various diseases’ like cancer and Alzheimer. It has a wide range of energy applications in batteries, solar cells, microwave, and Terahertz applications. It is a promising material on a nanoscale level, with favorable characteristics in spintronics and magnetoresistance. In this review, we will discuss MoS2 properties, structure and synthesis techniques with a focus on its applications and future challenges.

Germanane Monolayer Films as Antibacterial Coatings

Germanane (GeH), a graphane analogue, has attracted significant interest because of its optoelectronic properties; however, the environmental and biological effects of GeH have scarcely been investigated so far. Here we report a facile approach based on the Langmuir-Schaefer deposition to produce homogeneous and dense GeH monolayer films on various substrates. In view of possible applications and to extend the use of GeH to unexplored fields, we investigated its antibacterial activity for the first time and found that this promising 2D structure exhibits remarkable antibacterial activity against both Gram-negative and Gram-positive bacterial strains.

Bidirectional Superionic Conduction in Surface-Engineered 2D Hexagonal Boron Nitrides

We designed functionalized hexagonal boron nitride (FhBN) nanoflakes with high proton conductivity in both in- and through-plane directions as next generation polymer electrolyte membranes (PEMs) for energy storage and conversion systems. The synthesis and functionalization of hBN nanoflakes with sulfonic acid (SA) groups are obtained by one-step and in situ liquid-phase exfoliation with excellent dispersibility and stability over a period of three months. The physico/chemical properties of FhBN nanoflakes were investigated by different spectroscopic and microscopic characterization, confirming chemical interactions between hBN lattice and SA groups. High concentrations (65 and 75 wt %) of FhBN nanoflakes composed with Nafion solution formed stable FhBN-Nafion nanocomposite PEMs, offering extra proton conduction sites, doubling ion-exchange capacity, and reducing the swelling ratio compared to those of Nafion. Our results demonstrate that both the in-plane and through-plane proton conductivities of FhBN-Nafion PEMs significantly improve under various conditions comparative to that of Nafion. The maximum values of both in- and through-plane conductivities for FhBN75%-Nafion PEM at 80% of humidity and 80 °C are 0.41 and 0.1 S·cm^-1, respectively, which are 7 and 14 times higher than those of Nafion. The bidirectional superionic transport in highly concentrated FhBN PEMs is responsible for outstanding properties, useful for electrochemical energy devices.

Fate assessment of commercial 2D MoS2 aqueous dispersions at physicochemical and toxicological level

The physicochemical properties and the toxicological potential of commercially available MoS₂ nanoparticles with different lateral size and degradation stage were studied in the present research work. To achieve this, the structure and stoichiometry of fresh and old aqueous suspensions of micro-MoS₂ and nano-MoS₂ was analyzed by Raman, while x-ray photoelectron spectroscopy allowed to identify more quantitatively the nature of the formed oxidized species. A, the toxicological impact of the nanomaterials under analysis was studied using adenocarcinomic human alveolar basal epithelial cells (A549 cells) and the unicellular fungus S. cerevisiae as biological models. Cell viability assays and reactive oxygen species (ROS) determinations demonstrated different toxicity levels depending on the cellular model used and in function of the degradation state of the selected commercial nanoproducts. Both MoS₂ nanoparticle types induced sublethal damage on the A549 cells though the increase of intracellular ROS levels, while comparable concentrations reduced the viability of yeast cells. In addition, the old MoS₂ nanoparticles suspensions exhibited a higher toxicity for both human and yeast cells than the fresh ones. Our findings demonstrate that the fate assessment of nanomaterials is a critical aspect to increase the understanding on their characteristics and on their potential impact on biological systems along their life cycle.

Combating Actions of Green 2D-Materials on Gram Positive and Negative Bacteria and Enveloped Viruses

Interactions of novel bi-dimensional nanomaterials and live matter such as bacteria and viruses represent an extremely hot topic due to the unique properties of the innovative nanomaterials, capable in some cases to exhibit bactericide and antiviral actions. The interactions between bacteria and viruses and two dimensional nanosheets are here investigated. We extensively studied the interaction between a gram-negative bacterium, Escherichia coli, and a gram-positive bacterium, Staphylococcus aureus, with two different types of 2D nanoflakes such as MoS₂, belonging to the Transition Metal Dichalcogenides family, and Graphene Oxide. The same two types of nanomaterials were employed to study their antiviral action toward the Herpes simplex virus type-1, (HSV-1). The experimental results showed different bactericide impacts as well as different antiviral power between the two nanomaterials. The experimental findings were interpreted in bacteria on the base of the Derjaguin–Landau–Verwey–Overbeek theory. A simple kinetic model of bacterial growth in the presence of the interacting nanosheets is also elaborated, to explain the observed results. The experimental results in viruses are really novel and somewhat surprising, evidencing a stronger antiviral action of Graphene Oxide as compared to MoS₂. Results in viruses are complicated to quantitatively interpret due to the complexity of the system under study, constituted by virus/host cell and nanoflake, and due to the lack of a well assessed theoretical context to refer to. Thus, these results are interpreted in terms of qualitative arguments based on the chemical properties of the interactors in the given solvent medium.

Spectroscopic Properties of Two 5'-(4-Dimethylamino)Azobenzene Conjugated G-Quadruplex Forming Oligonucleotides

The synthesis of two 5'-end (4-dimethylamino)azobenzene conjugated G-quadruplex forming aptamers, the thrombin binding aptamer (TBA) and the HIV-1 integrase aptamer (T30695), was performed. Their structural behavior was investigated by means of UV, CD, fluorescence spectroscopy, and gel electrophoresis techniques in K+-containing buffers and water-ethanol blends. Particularly, we observed that the presence of the 5'-(4-dimethylamino)azobenzene moiety leads TBA to form multimers instead of the typical monomolecular chair-like G-quadruplex and almost hampers T30695 G-quadruplex monomers to dimerize. Fluorescence studies evidenced that both the conjugated G-quadruplexes possess unique fluorescence features when excited at wavelengths corresponding to the UV absorption of the conjugated moiety. Furthermore, a preliminary investigation of the trans-cis conversion of the dye incorporated at the 5'-end of TBA and T30695 showed that, unlike the free dye, in K+-containing water-ethanol-triethylamine blend the trans-to-cis conversion was almost undetectable by means of a standard UV spectrophotometer.

Exploring Graphene and MoS2 Chips Based Surface Plasmon Resonance Biosensors for Diagnostic Applications

Until now, two-dimensional (2D) nanomaterials have been widely studied and applied in the biosensor field. Some of the advantages offered by these 2D materials include large specific surface area, high conductivity, and easy surface modification. This review discusses the use of 2D material in surface plasmon resonance (SPR) biosensor for diagnostic applications. Two-dimensional material reviewed includes graphene and molybdenum disulfide (MoS2). The discussion begins with a brief introduction to the general principles of the SPR biosensor. The discussion continues by explaining the properties and characteristics of each material and its effect on the performance of the SPR biosensor, in particular its sensitivity. This review concludes with some recent applications of graphene- and MoS2-based SPR biosensor in diagnostic applications.

2D materials in electrochemical sensors for in vitro or in vivo use

Individual cells and cell populations are at the present time investigated with a myriad of analytical tools. While most of them are commercially available, some of these analytical tools are just emerging from research laboratories and are in the developmental phase. Electrochemical sensors which allow the monitoring of low molecular weight compounds released (and / or uptaken) by cells are among these emerging tools. Such sensors are increasingly built using 2D materials (e.g. graphene-based materials, transition metal dichalcogenides, etc.) with the aim of conferring better analytical performances to these devices. The present work critically reviews studies published during the last 10 years describing electrochemical sensors made with 2D materials and exploited to monitor small compounds (e.g. H₂O₂, ·NO, glucose, etc.) in living biological systems. It also discusses the very few 2D material-based electrochemical sensors which are wearable or usable in vivo. Finally, the present work includes a specific section about 2D material biocompatibility, a fundamental requirement for 2D material-based sensor applications in vitro and in vivo. As such, the review provides a critical view on the state of the art of electrochemical sensors made with 2D materials and used at cellular level and it evaluates the possibility that such sensors will be used on / in the human body on a wider scale.

Fluorescent Polymer-MoS2-Embedded Microgels for Photothermal Heating and Colorimetric Monitoring

Photothermal heating with accurate monitoring of local temperature in complex biological fluids is crucial for therapeutic accuracy. Herein, photothermal microgels are developed to heat microscopic volumes through photothermal conversion and report the local temperature with a colorimetric response. The microgels consist of poly(ethylene glycol)-based hydrogels, which integrate temperature-responsive block-copolymer-grafted MoS₂ nanosheets (BCP-grafted MoS₂ NSs). The MoS₂ NSs are used as a fluorescence quencher as well as an efficient photothermal agent, with their surface decorated with three distinct temperature-responsive BCPs containing blue-, green-, and red-fluorescent dyes. Upon irradiation of near-infrared light, MoS₂ NSs convert the radiation into heat, and the BCPs change their conformation depending on the local temperature, selectively activating Förster resonance energy transfer of the three dyes. The use of three distinct BCPs and dyes enables the measurement of temperature in a wide range (i.e., from 25 to 50 °C). Importantly, the hydrogel matrix excludes molecules larger than the limiting mesh size so that BCP-grafted MoS₂ NSs remain free from contamination against large adhesive proteins such as albumin, thus maintaining their sensitivity even in complex fluids.

Passively Mode-Locked Fiber Laser with WS2/SiO2 Saturable Absorber Fabricated by Sol-Gel Technique

High-performance ultrafast fiber lasers require saturable absorbers (SAs) of high optical damage threshold and high operation stability. Here, the optical properties and application of the WS₂/SiO₂ SA prepared by the sol-gel method are reported. SiO₂ prepared by sol-gel technique has similar properties to fiber in ultrafast fiber lasers, such as mechanical strength, refractive index, optical transmission, and absorption. For the SA device by the sol-gel method combined with WS₂ material, not only will the additional scattering loss not be introduced, but also, the damage threshold of the SA device can be effectively increased. Furthermore, SA material is wrapped by SiO₂, which insulates the influence of the external environment. Based on the first preparation of the WS₂/SiO₂ glass SA, stable soliton pulses are obtained in ytterbium-doped fiber lasers (YDFLs) with a pulse width of 58 ps, an average output power of 56.8 mW, and a repetition rate of 19.03 MHz. In addition, a stable mode-locked operation with a pulse width of 325 fs and an output power of 39.6 mW is also achieved in an erbium-doped fiber laser (EDFL). These results demonstrate that the WS₂/SiO₂ glass prepared by the sol-gel method can significantly increase laser output power and shorten pulse width in the fiber laser, which provides a new opportunity for the traditional preparation method of the SA device.

A two-step gas/liquid strategy for the production of N-doped defect-rich transition metal dichalcogenide nanosheets and their antibacterial applications

Herein, we developed a general two-step gas expansion and exfoliation strategy based on a urea-assisted hydrothermal process combined with sonication exfoliation for the production of nitrogen (N)-doped plus defect-rich transition metal dichalcogenide (TMD) nanosheets (NSs) such as N-MoS₂ and N-WS₂ NSs. The interlayers of bulk MoS₂ (or WS₂) were expanded with urea molecules dissolved in distilled water, which were decomposed to NH₃ during the hydrothermal process. Simultaneously, sulfur atoms were partly replaced by N atoms to achieve N doping. Subsequently, sonication exfoliation of the urea-treated bulk MoS₂ (or WS₂) promoted the production of defect-rich NSs. Importantly, the defect-rich N-MoS₂ and N-WS₂ NSs exhibit enhanced peroxidase-like catalytic activity after being captured by bacteria, and can catalyze hydrogen peroxide (H₂O₂) to produce more toxic hydroxyl radicals (˙OH) than non-N-doped MoS₂ or WS₂ NSs. As a result, the N-MoS₂ or N-WS₂ NSs were capable of effectively killing Gram-negative ampicillin resistant Escherichia coli (Amp^rE. coli) and Gram-positive endospore-forming Bacillus subtilis (B. subtilis) and promoting bacteria-infected wound healing. This work not only provides a simple, universal exfoliation strategy for producing defect-rich N-doped TMD NSs but also provides a promising catalytic antibacterial option and has potential for many other catalytic applications.

Visible light driven MoS2/α-NiMoO4 ultra-thin nanoneedle composite for efficient Staphylococcus aureus inactivation

MoS₂/α-NiMoO₄ ultra-thin nanoneedle composite was synthesized by microwave hydrothermal process in one step. The nanocomposite revealed the complete destruction of multidrug resistant Staphylococcus aureus (S. aureus) within 150 min under visible light irradiation. According to electron spin resonance measurement and radical trapping experiment, it has been established that O₂¯ acts as a major active species for bacterial inactivation in visible light. The bacterial inactivation was further proved by membrane deformities in bacterial cell membrane, DNA fragmentation, and protein destruction. TEM- elemental mapping confirms the inactivation of S. aureus by reactive oxygen species (ROS) but not the toxicity of photocatalyst. Transient photocurrent responses, electrochemical impedance spectroscopy, and cyclic voltammetry measurements reveal the efficient separation of electron-hole pairs in the composite photocatalyst. The composite photocatalyst shows greater ROS production, higher degree of DNA fragmentation and protein degradation, detrimental effects on the morphology of the bacterial cell wall, outstanding transient photocurrent responses, reduction of interfacial charge transfer resistance, superb oxidation/reduction potential, strong visible light absorption, and adequate separation of photogenerated electron-hole pairs as compared to host photocatalyst. The photocatalytic inactivation mechanism was explained. So, this promising composite photocatalyst can be applied for inactivation of multidrug resistant bacteria in biological waste water.

Two-Dimensional Nanosheet-Based Photonic Nanomedicine for Combined Gene and Photothermal Therapy

Two-dimensional (2D) nanosheets are characterized by their ultra-thin structure which sets them apart from their bulk materials. Due to this unique 2D structure, they have a high surface-to-volume ratio that can be beneficial for the delivery of various drugs including therapeutic DNAs and RNAs. In addition, various 2D materials exhibit excellent photothermal conversion efficiency when exposed to the near infrared (NIR) light. Therefore, this 2D nanosheet-based photonic nanomedicine has been gaining tremendous attention as both gene delivering vehicles and photothermal agents, which create synergistic effects in the treatment of different diseases. In this review, we briefly provide an overview of the following two parts regarding this type of photonic nanomedicine: (1) mechanism and advantages of nanosheets in gene delivery and photothermal therapy, respectively. (2) mechanism of synergistic effects in nanosheet-mediated combined gene and photothermal therapies and their examples in a few representative nanosheets (e.g., graphene oxide, black phosphorus, and translational metal dichalcogenide). We also expect to provide some deep insights into the possible opportunities associated with the emerging 2D nanosheets for synergistic nanomedicine research.

A bioconjugated MoS2 based nanoplatform with increased binding efficiency to cancer cells

Preparation and study of a MoS₂ nanosheet based nanoplatform for a cancer detection and treatment system equipped with an antibody–antigen based recognition element.

Inhibition of Histone Demethylases LSD1 and UTX Regulates ERα Signaling in Breast Cancer

In breast cancer, Lysine-specific demethylase-1 (LSD1) and other lysine demethylases (KDMs), such as Lysine-specific demethylase 6A also known as Ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX), are co-expressed and co-localize with estrogen receptors (ERs), suggesting the potential use of hybrid (epi)molecules to target histone methylation and therefore regulate/redirect hormone receptor signaling. Here, we report on the biological activity of a dual-KDM inhibitor (MC3324), obtained by coupling the chemical properties of tranylcypromine, a known LSD1 inhibitor, with the 2OG competitive moiety developed for JmjC inhibition. MC3324 displays unique features not exhibited by the single moieties and well-characterized mono-pharmacological inhibitors. Inhibiting LSD1 and UTX, MC3324 induces significant growth arrest and apoptosis in hormone-responsive breast cancer model accompanied by a robust increase in H3K4me2 and H3K27me3. MC3324 down-regulates ERα in breast cancer at both transcriptional and non-transcriptional levels, mimicking the action of a selective endocrine receptor disruptor. MC3324 alters the histone methylation of ERα-regulated promoters, thereby affecting the transcription of genes involved in cell surveillance, hormone response, and death. MC3324 reduces cell proliferation in ex vivo breast cancers, as well as in breast models with acquired resistance to endocrine therapies. Similarly, MC3324 displays tumor-selective potential in vivo, in both xenograft mice and chicken embryo models, with no toxicity and good oral efficacy. This epigenetic multi-target approach is effective and may overcome potential mechanism(s) of resistance in breast cancer.