Valleytronics in bulk MoS2 with a topologic optical field.

The valley degree of freedom1-4 of electrons in materials promises routes towards energy-efficient information storage with enticing prospects for quantum information processing5-7. Current challenges in utilizing valley polarization are symmetry conditions that require monolayer structures8,9 or specific material engineering10-13, non-resonant optical control to avoid energy dissipation and the ability to switch valley polarization at optical speed. We demonstrate all-optical and non-resonant control over valley polarization using bulk MoS2, a centrosymmetric material without Berry curvature at the valleys. Our universal method utilizes spin angular momentum-shaped trefoil optical control pulses14,15 to switch the material's electronic topology and induce valley polarization by transiently breaking time and space inversion symmetry16 through a simple phase rotation. We confirm valley polarization through the transient generation of the second harmonic of a non-collinear optical probe pulse, depending on the trefoil phase rotation. The investigation shows that direct optical control over the valley degree of freedom is not limited to monolayer structures. Indeed, such control is possible for systems with an arbitrary number of layers and for bulk materials. Non-resonant valley control is universal and, at optical speeds, unlocks the possibility of engineering efficient multimaterial valleytronic devices operating on quantum coherent timescales.

Separation of inorganic anions on reversed-phase C18 columns with a phosphomolybdate mobile phase.

Reversed-phase high performance liquid chromatography (RP-HPLC) is the most widely used chromatographic method. In addition to hydrophobic interactions, additional interactions such as electrostatic interactions may participate in the retention behaviour of an analyte. This makes it possible to use RP-HPLC for many types of analyte. We describe a simple method for separating inorganic anions on a C18 column, in which retention of inorganic anions is almost entirely due to electrostatic interactions. This leads to rapid separations as well as higher theoretical plate numbers. We used 2 mM phosphoric acid containing a low concentration of disodium molybdate as the mobile phase, which allows UV detection of non-UV-absorbing anions. With this method, we determined eight inorganic anions including several non-UV-absorbing anions photometrically at 220 nm. The detection limits of the examined eight inorganic anions calculated at a signal-to-noise ratio of 3 were between 0.3 and 10 µM. The detector response was linear over three orders of magnitude of inorganic anion concentration. The proposed RP-HPLC/UV method was successfully applied to determine inorganic anions in some water samples.

Systematic inspection on the interplay between MoNa-induced sodium and the formation of MoSe2 intermediate layer in CIGSe/Mo heterostructures.

The critical impact of sodium-doped molybdenum (MoNa) in shaping the MoSe2 interfacial layer, influencing the electrical properties of CIGSe/Mo heterostructures, and achieving optimal MoSe2 formation conditions, leading to improved hetero-contact quality. Notably, samples with a 600-nm-thick MoNa layer demonstrate the highest resistivity (73 µΩcm) and sheet resistance (0.45 Ω/square), highlighting the substantial impact of MoNa layer thickness on electrical conductivity. Controlled sodium diffusion through MoNa layers is essential for achieving desirable electrical characteristics, influencing Na diffusion rates, grain sizes, and overall morphology, as elucidated by EDX and FESEM analyses. Additionally, XRD results provide insights into the spontaneous peeling-off phenomenon, with the sample featuring a ~ 600-nm MoNa layer displaying the strongest diffraction peak and the largest crystal size, indicative of enhanced Mo to MoSe2 conversion facilitated by sodium presence. Raman spectra further confirm the presence of MoSe2, with its thickness correlating with MoNa layer thickness. The observed increase in resistance and decrease in conductivity with rising MoSe2 layer thickness underscore the critical importance of optimal MoSe2 formation for transitioning from Schottky to ohmic contact in CIGSe/Mo heterostructures. Ultimately, significant factors to the advancement of CIGSe thin-film solar cell production are discussed, providing nuanced insights into the interplay of MoNa and MoSe2, elucidating their collective impact on the electrical characteristics of CIGSe/Mo heterostructures.

An NIR-II-enhanced nanozyme to promote wound healing in methicillin-resistant Staphylococcus aureus infections.

Deep tissue bacterial infections, especially methicillin-resistant Staphylococcus aureus (MRSA) infections, pose challenges to clinical therapy due to their low debridement efficiency and relapsing. Molybdenum disulfide (MoS2) is used in the antibacterial field as a classic photothermal agent (NIR-I) with good biocompatibility. However, due to its limited NIR-I tissue penetration ability and single treatment mode, MoS2 has poor therapeutic effects on deep tissue infection. Herein, we prepared a defect-type hybrid 2H-MoS2 nanozyme (MoWS2) using hydrothermal method fabricate the MoWS2 composite, which is a new antibacterial strategy involving photothermal and enzyme catalysis, and further enhances the activity of the nanozyme through overheating. The regulation of 2H-MoS2 defects through tungsten ion doping endows MoWS2 with better near-infrared two-region absorption (NIR-II) and enzyme catalytic performance. Antibacterial activity experiments in vitro have shown that MoWS2 can achieve efficient bactericidal activity and biofilm clearance through hyperthermia and reactive oxygen species (ROS). Deep MRSA infection experiments have shown that MoWS2 rapidly removes bacteria from subcutaneous infected tissues through photothermal therapy (PTT) and chemodynamic therapy (CDT), accelerates the dissipation of abscesses, and promotes the healing of infected wounds. Additionally, the versatile treatment mode of MoWS2 was further confirmed through tissue sectioning and immunofluorescence staining analysis. Overall, these results provide a feasible approach for achieving efficient treatment of deep tissue infections through tungsten ion doping to regulate defective 2H-MoS2. STATEMENT OF SIGNIFICANCE: The photothermal effect of MoS2 nanosheets in the NIR-I (650-900 nm) window in anti-MRSA therapy is considered to be highly reliable and efficient in PTA. However, most of the developed PPT therapies or antimicrobial systems based on PTT therapies developed with 1T-MoS2 have in vivo sterilization temperatures of more than 55°C, which have the risk of damaging the normal tissues of the skin. In this study, we prepared W@MoS2 with a good photothermal effect (36.9%) in the NIR-II window and good peroxidase-like activity. The combined effect of PTT and CDT has a stronger bactericidal effect while avoiding high-temperature damage, which makes the W@MoS2 material more advantageous in terms of antimicrobial effect.

A Co-Reactive Immunosensor Based on Ti3C2Tx MXene@TiO2-MoS2 Hybrids Promoting luminol@Au@Ni-Co NCs Electrochemiluminescence for CYFRA 21-1 Detection.

The construction of assays is capable of accurately detecting cytokeratin-19 (CYFRA 21-1), which is critical for the rapid diagnosis of nonsmall cell lung cancer. In this work, a novel electrochemiluminescence (ECL) immunosensor based on the co-reaction promotion of luminol@Au@Ni-Co nanocages (NCs) as ECL probe by Ti3C2Tx MXene@TiO2-MoS2 hybrids as co-reaction accelerator was proposed to detect CYFRA 21-1. Ni-Co NCs, as a derivative of Prussian blue analogs, can be loaded with large quantities of Au NPs, luminol, and CYFRA 21-1 secondary antibodies due to their high specific surface area. To further improve the sensitivity of the developed ECL immunosensor, Ti3C2Tx MXene@TiO2-MoS2 hybrids were prepared by in situ growth of TiO2 nanosheets on highly conductive Ti3C2Tx MXene, and MoS2 was homogeneously grown on Ti3C2Tx MXene@TiO2 surfaces by the hydrothermal method. Ti3C2Tx MXene@TiO2-MoS2 hybrids possess excellent catalytic performance on the electro-redox of H2O2 generating more O2·- and obtaining optimal ECL intensity of the luminol/H2O2 system. Under the appropriate experimental conditions, the quantitative detection range of CYFRA 21-1 was from 0.1 pg mL-1 to 100 ng mL-1, and the limit of detection (LOD) was 0.046 pg mL-1. The present sensor has a lower LOD with a wider linear range, which provides a new analytical assay for the early diagnosis of small-cell-type lung cancer labels.

An insight into the dual role of MoS2-based nanocarriers in anticancer drug delivery and therapy.

Over the years, nanomaterials have been exploited as drug delivery systems and therapeutic agents in cancer treatment. Special emphasis has been placed on structure and shape-mediated drug loading and release. Functional materials, including molybdenum disulfide (MoS2), have shown promising results because of their tunable structure and unmatched physicochemical properties. Specifically, easy surface functionalization and high drug adsorption ability make them ideal candidates. Although the large surface area of nanosheets/nanoflakes may result in high drug loading, the encapsulation efficiency is better for MoS2 nanoflower structures. Due to its high targeting abilities, the loading of chemotherapeutic drugs onto MoS2 may minimize nonspecific cellular death and undesired side effects. Furthermore, due to their strong light-absorption ability, MoS2 nanostructures have been widely exploited as photothermal and photodynamic therapeutic agents. The unexplored dimensions of cancer therapy, including chemodynamic (Fenton-like reaction) and piezo-catalytic (ultrasound-mediated reactive oxygen generation), have been recently unlocked, in which the catalytic properties of MoS2 are utilized to generate toxic free radicals to eliminate cancer. Intriguingly, combining these therapeutic modalities often results in high therapeutic efficacy at low doses and minimizes side effects. With a plethora of recent studies, a thorough analysis of current findings is crucial. Therefore, this review discusses the major advances in this field of research. A brief commentary on the limitations/future outlook/ethical issues of the clinical translation of MoS2-mediated cancer treatments is also deliberated. Overall, in our observations, the MoS2-based nanoformulations hold great potential for future cancer therapy applications. STATEMENT OF SIGNIFICANCE: Development of nanomedicines based on MoS2 has opened new avenues in cancer treatment. The MoS2 with different morphologies (nanosheet/nanoflower/QDs) has shown promising results in controlled and targeted drug delivery, leading to minimized side effects and increased therapeutic efficacy. While existing reviews have primarily focused on the optical/thermal properties utilized in photodynamic/photothermal therapy, the outstanding catalytic properties of MoS2 utilized in cancer therapies (chemodynamic/piezo-catalytic) are often overlooked. This review critically highlights and praises/criticizes individual articles reporting the MoS2-based nanoplatforms for cancer therapy applications. Additionally, MoS2-based combined therapies for synergistic effects are discussed. Furthermore, a brief commentary on the future prospects for clinical translations is also deliberated, which is appealing to various research communities engaged in cancer theranostics and biomedical sciences research.

Chitosan derived N-doped carbon anchored Co3O4-doped MoS2 nanosheets as an efficient peroxymonosulfate activator for degradation of dyes.

Peroxymonosulfate (PMS), which is dominated by non-free radical pathway, has a good removal effect on organic pollutants in complex water matrices. In this article, a biodegradable cobalt-based catalyst (Co3O4/MoS2@NCS) was synthesized by a simple hydrothermal method with chitosan (CS) as nitrogen­carbon precursor and doped with Cobaltic­cobaltous oxide (Co3O4) and Molybdenum disulfide (MoS2), and was used to activate PMS to degrade dye wastewater. Electrochemical tests showed that Co3O4/MoS2@NCS exhibited higher current density and cycling area than MoS2@NCS and MoS2. In the Co3O4/MoS2@NCS/PMS system, the degradation rate of 30 mg·L-1 rhodamine B (RhB) reached 97.75 % within 5 min, and kept as high as 94.34 % after 5 cycles. Its rate constant was 1.91 and 8.37 times that of MoS2@NCS/PMS and MoS2/PMS, respectively. It had good complex background matrices and acid-base anti-interference ability, and had good universality and reusability. The degradation rate of methyl orange (MO) and methylene blue (MB) were more than 91 % within 5 min at pH 4.8. The experimental results demonstrated that MoS2-modified CS as a carrier exposed a large number of active sites, which not only dispersed Co3O4 nanoparticles and improved the stability of the catalyst, but also provided abundant electron rich groups, and promoted the activation of PMS and the production of reactive oxygen species (ROS). PMS was effectively activated by catalytic sites (Co3+/Co2+, Mo4+/Mo5+/Mo6+, CO, pyridine N, pyrrole N, hydroxyl group and unsaturated sulfur), producing a large number of radicals that attack RhB molecules, causing chromophore cleavage, ring opening, and mineralization. Among them, non-free radical 1O2 was the main ROS for RhB degradation. This work is expected to provide a new idea for the design and synthesis of environmentally friendly and efficient MoS2-modified cobalt-based catalysts.

MoS2-based nanocomposites and aerogels for antibiotic pollutants removal from wastewater by photocatalytic degradation process: A review.

Photocatalytic technologies based on molybdenum disulfide (MoS2) catalysts are effective, eco-friendly, and promising for antibiotic pollutants treatment. The technologies used by MoS2-based nanocomposites and aerogels for efficient degradation of antibiotics are reviewed in detail for the first time in this paper. The fundamental aspects of MoS2 were comprehensively scrutinized, encompassing crystal structure, optical properties, and photocatalytic principle. Then, the main synthesized methods and advantages/disadvantages for the preparation of MoS2-based nanocomposites and aerogels were systematically presented. Besides, a comprehensive overview of diverse MoS2-based nanocomposites and aerogels photo-degradation systems that enhanced the degradation of antibiotic pollutants were revealed. Meanwhile, the photo-degradation mechanism concentrated on the photoelectron transfer pathways and reactive oxygen species (ROS) were systematically evaluated. Finally, the challenges and perspectives for deeply development of MoS2-based nanocomposites and aerogels were discussed. This review may help researchers to deeply understand the research status of MoS2-based nanocomposites and aerogels for antibiotics removal, and makes clear the photo-degradation mechanism from photoelectron transfer pathways and ROS aspects of MoS2-based nanocomposites and aerogels.

A novel electrode for simultaneous detection of multiple heavy metal ions without pre-enrichment in food samples.

Integrating a pre-enrichment step into electrochemical detection methodologies has traditionally been employed to enhance the performance of heavy metal detection. However, this augmentation also introduces a degree of intricacy into the sensing process and increases energy consumption. In this work, Mo-doped WO3 is grown in situ on carbon cloth by one-step electrodeposition. The electrode detect multiple heavy metal ions simultaneously in the range of 0.1-100.0 µM with LODs ranging from 11.2 to 17.1 nM. The electrode successfully detected heavy metal ions in diverse food samples. This pioneering detection strategy realized the direct and simultaneous detection of multiple heavy metal ions by utilizing the valence property of WO3 and oxygen vacancies generated by molybdenum doping. The Mo-WO3/CC pre-enrichment-free detection electrode boasts straightforward preparation, a streamlined detection procedure, swift response kinetics, and superior performance relative to previously reported electrodes, which makes it possible to develop a portable heavy metal ion detection device.

Green Nanopesticide: pH Response and Molybdenum Selenide Carrier with Photothermal Effect to Transport Prochloraz to Inhibit Sclerotinia Disease.

Accurate pesticide delivery is a key factor in improving pesticide utilization, which can effectively reduce the use of pesticides and environmental risks. In this study, we developed a nanocarrier preparation method which can be controlled by pH/near-infrared response. Mesoporous molybdenum selenide (MoSe2) with a high loading rate was used as the core, poly(acrylic acid) (PAA) with acid response was used as the shell, and prochloraz (Pro) was loaded to form a pH-/near-infrared-responsive core-shell nanosystem (Pro@MoSe2@PAA NPs, abbreviated as PMP). Sclerotinia sclerotiorum infection secretes oxalic acid, forming an acidic microenvironment. In an acidic environment, PMP could quickly release Pro, and the cumulative release amount of Pro at pH = 5.0 was 3.1 times higher than that at pH = 7.4, and the efficiency of releasing Pro in the acidic environment was significantly enhanced. In addition, the release rate of PMP under near-infrared light irradiation was also significantly improved, and the cumulative release of Pro under simulated sunlight was 2.35 times higher than that under no light. The contact angles of PMP droplets on rapeseeds were reduced by 31.2 and 13.9% compared to Pro and MoSe2, respectively, which proved that the nanosystems had good wettability. In addition, PMP shows excellent adhesion and resistance to simulated rain washout. In the plate antibacterial experiment, the inhibitory effect of 0.5 µg/mL PMP on S. sclerotiorum was as high as 75.2% after 6 days, which showed a higher bactericidal activity than Pro. More importantly, PMP shows excellent biocompatibility and safety to plants, microorganisms, and cells. In a word, PMP is a green nanopesticide with a dual response of pH/near-infrared light, which provides a new strategy for the sustainable development of agriculture.

Adsorption behavior of Mo(VI) from aqueous solutions using tungstate-modified magnetic nanoparticle.

A new magnetic nanoparticle modified with sodium tungstate (Mnp-Si-W) was synthesized and employed for the sorption of molybdenum from aqueous solutions. The prepared nanoparticles (Mnp-Si-W) were characterized by different advanced techniques. Different parameters that influenced the adsorption percent of Mo(VI) were investigated using a batch process. Based on a systematic investigation of the adsorption isotherms and kinetics models, Mo(VI) adsorption follows the Langmuir model and pseudo-second-order kinetics. According to the Langmuir isotherm model, the Mnp-Si-W nanoparticles exhibited a maximum adsorption capacity of 182.03 mg g-1 for Mo(VI) at pH 2.0. The effect of competing ions showed that the prepared nanoparticles have a high selectivity for the sorption of molybdenum. Moreover, the effect of some interfering anions on Mo(VI) ion sorption is found in the following order: phosphate < sulfate < chromate. Finally, the nanoparticle (Mnp-Si-W) can be successfully reused five times.

PEGylated Molybdenum-Iodine Nanocluster as a Promising Radiodynamic Agent against Prostatic Adenocarcinoma.

The combination of photodynamic therapy and radiotherapy has given rise to a modality called radiodynamic therapy (RDT), based on reactive oxygen species-producing radiosensitizers. The production of singlet oxygen, O2(1Δg), by octahedral molybdenum (Mo6) clusters upon X-ray irradiation allows for simplification of the architecture of radiosensitizing systems. In this context, we prepared a radiosensitizing system using copper-free click chemistry between a Mo6 cluster bearing azido ligands and the homo-bifunctional linker bis-dPEG11-DBCO. The resulting compound formed nanoparticles, which featured production of O2(1Δg) and efficient cellular uptake, leading to remarkable photo- and radiotoxic effects against the prostatic adenocarcinoma TRAMP-C2 cell line. Spheroids of TRAMP-C2 cells were also used for evaluation of toxicity and phototoxicity. In vivo experiments on a mouse model demonstrated that subcutaneous injection of the nanoparticles is a safe administration mode at a dose of up to 0.08 g kg-1. The reported results confirm the relevancy of Mo6-based radiosensitizing nanosystems for RDT.

A simple photoelectrochemical aptasensor based on MoS2/rGO for aflatoxin B1 detection in grain crops.

Designing a simple and sensitive photoelectrochemical (PEC) sensor is crucial to addressing the limitations of routine analytical methods. The sensitivity of the PEC sensor, however, relies on the photoelectric material used. In this manuscript, composites of MoS2/rGO (MG) with a large area and layered structure are prepared by simple steps. This material exhibits sensitivity to visible light and demonstrates outstanding photoelectric conversion performance. The constructed PEC aptasensor using this material to detect aflatoxin B1 (AFB1) shows significantly higher sensitivity and stability compared to similar sensors. This may be attributed to the presence of surface defects in MoS2, which provide more active sites for photocatalysis. Additionally, graphene oxide (GO) is reduced to rGO by thiourea and forms a heterojunction with MoS2, enhancing charge carrier separation and interfacial electron transfer. Our research has revealed that the photocurrent intensity of the aptamer electrode decreases with an increase in AFB1 concentration, resulting in a "signal-off" PEC aptasensor. The detection limit of this aptasensor is 2.18 pg mL-1, with a linear range of 0.001 to 100 ng mL-1. This result will also provide a reference for the study of other mycotoxins in food.

Valorization of sugarcane bagasse with in situ grown MoS2 for continuous pollutant remediation and microbial decontamination.

In this study, sugarcane bagasse (SB) was strategically subjected to a delignification process followed by the in situ growth of multi-layered molybdenum disulfide (MoS2) nanosheets with hexagonal phase (2H-phase) crystal structure via hydrothermal treatment. The MoS2 nanosheets underwent self-assembly to form nanoflower-like structures in the aligned cellulose inter-channels of delignified sugarcane bagasse (DSB), the mechanism of which was understood through FTIR and XPS spectroscopic studies. DSB, due to its porous morphology and abundant hydroxyl groups, shows remediation capabilities of methylene blue (MB) dye through physio-sorption but shows a low adsorption capacity of 80.21 mg/g. To improve the removal capacity, DSB after in situ growth of MoS2 (DSB-MoS2) shows enhanced dye degradation to 114.3 mg/g (in the dark) which further improved to 158.74 mg/g during photodegradation, due to catalytically active MoS2. Interestingly, DSB-MoS2 was capable of continuous dye degradation with recyclability for three cycles, reaching an efficiency of > 83%, along with a strong antibacterial response against Gram-positive Staphylococcus aureus (S.aureus) and Gram-negative Escherichia coli (E. coli). The present study introduces a unique strategy for the up-conversion of agricultural biomass into value-added bio-adsorbents, which can effectively and economically address the remediation of dyes with simultaneous microbial decontamination from polluted wastewater streams.

Fabrication of label-free immunoprobe for monkeypox A29 detection using one-step electrodeposited molybdenum oxide-graphene quantum rods.

Monkeypox is a zoonotic viral infection caused by the monkeypox virus (MPXV), which belongs to the Poxviridae family of the Orthopoxvirus (OPXV) genus. Monkeypox is transmitted from animals to humans and humans to humans; therefore, the accurate and early detection of MPXV is crucial for reducing mortality. A novel graphene-based material, graphene quantum rods (GQRs) was synthesized and confirmed using high-resolution transmission electron microscopy (HR-TEM) and atomic force microscopy (AFM). In this study, molybdenum oxide was electrodeposited and one-pot electrodeposition of MoO3-GQRs composite on carbon fiber paper (CFP) enabled by an antibody (Ab A29)/MoO3-GQRs immunoprobe was developed for the early diagnosis of MPXV protein (A29P). Several studies were conducted to analyze the MoO3-GQRs composite, and the prepared Ab A29/MoO3-GQRs immunoprobe selectively bound to the A29P antigen that was measured using differential pulse voltammetry (DPV) analysis and impedance spectroscopy. The antigen-antibody interaction was analyzed using X-ray photoelectron spectroscopy. DPV analysis showed a wide linear range of detection from 0.5 nM to 1000 nM, a detection limit of 0.52 nM, and a sensitivity of 4.51 µA in PBS. The prepared immunoprobe was used to analyze A29P in serum samples without reducing electrode sensitivity. This system is promising for the clinical analysis of A29P antigen and offers several advantages, including cost-effectiveness, ease of use, accuracy, and high sensitivity.

Pseudouridine-modified RNA probe for label-free electrochemical detection of nucleic acids on 2D MoS2 nanosheets.

RNA modification, particularly pseudouridine (Ψ), has played an important role in the development of the mRNA-based COVID-19 vaccine. This is because Ψ enhances RNA stability against nuclease activity and decreases the anti-RNA immune response. Ψ also provides structural flexibility to RNA by enhancing base stacking compared with canonical nucleobases. In this report, we demonstrate the first application of pseudouridine-modified RNA as a probe (Ψ-RNA) for label-free nucleic acid biosensing. It is known that MoS2 has a differential affinity for nucleic acids, which may be translated into a unique electronic signal. Herein, the Ψ-RNA probe interacts with the pristine MoS2 surface and causes a change in interfacial electrochemical charge transfer in the MoS2 nanosheets. Compared with an unmodified RNA probe, Ψ-RNA exhibited faster adsorption and higher affinity for MoS2. Moreover, Ψ-RNA could bind to complementary RNA and DNA targets with almost equal affinity when engaged with the MoS2 surface. Ψ-RNA maintained robust interactions with the MoS2 surface following the hybridization event, perhaps through its extra amino group. The detection sensitivity of the Ψ-RNA/MoS2 platform was as low as 500 attomoles, while the results also indicate that the probe can distinguish between complementary targets, single mismatches, and non-complementary nucleic acid sequences with statistical significance. This proof-of-concept study shows that the Ψ-RNA probe may solve numerous problems of adsorption-based biosensing platforms due to its stability and structural flexibility.

Hemin/G-quadruplex and AuNPs-MoS2 based novel dual signal amplification strategy for ultrasensitively sandwich-type electrochemical thrombin aptasensor.

In this work, a novel sandwich-type electrochemical aptasensor based on the dual signal amplification strategy of hemin/G-quadruplex and AuNPs-MoS2 was designed and constructed, which realized the highly sensitive and specific detection of thrombin (TB). In this aptasensor, the 15-mer TB-binding aptamer (TBA-1) modified with thiol group was immobilized on the surface of AuNPs modified glassy carbon electrode (AuNPs/GCE) as capturing elements. Another thiol-modified 29-mer TB-binding aptamer (TBA-2) sequence containing G-quadruplex structure for hemin immobilization was designed. The formed hemin/G-quadruplex/TBA-2 sequence was further combined to the AuNPs decorated flower-like molybdenum disulfide (AuNPs-MoS2) composite surface via Au-S bonds, acting the role of reporter probe. In presence of the target TB, the sandwich-type electrochemical aptamer detection system could be formed properly. With the assistance of the dual signal amplification of AuNPs-MoS2 and hemin/G-quadruplex toward H2O2 reduction, the sandwich-type electrochemical aptasensor was successfully constructed for sensitive detection of TB. The results demonstrate that the fabricated aptasensor displays a wide linear range of 1.0 × 10-6 âˆ¼ 10.0 nM with a low detection limit of 0.34 fM. This proposed aptasensor shows potential application in the detection of TB content in real biological samples with high sensitivity, selectivity, and reliability.

Dual-mode self-powered photoelectrochemical and colorimetric determination of procalcitonin accomplished by multienzyme-expressed Ni4Cu2 bimetallic hollow nanospheres and spherical nanoflower-MoS2/Cu2ZnSnS4/Bi2S3.

Bacterial infections, viral infections and autoimmune diseases pose a considerable threat to human health. Procalcitonin (PCT) has emerged as a biomarker for the detection of these diseases. To ensure accurate and reliable results, we propose a dual-mode approach that incorporates self-validation and self-correction mechanisms. Herein, we develop a dual-mode self-powered photoelectrochemical (PEC) and colorimetric sensor to determine PCT. The self-powered PEC sensor was constructed with a photoanode of spherical nanoflower-MoS2/Cu2ZnSnS4/Bi2S3 material and a photocathode of CuInS2 material. Ni4Cu2 bimetallic hollow nanospheres (BHNs) possess superoxide dismutase and catalase performance, which facilitate superoxide anion radical (·O2-) and H2O2 circulating generation, promoting the separation of photogenerated electrons and holes to amplify photocurrent signal. Thus Ni4Cu2 BHNs is used as a marker material for PEC sensor. Meanwhile, in colorimetric mode, Ni4Cu2 BHNs converts blue oxTMB to a colourless TMB for colorimetric detection of PCT. Based on this principle, dual-mode determination of PCT with high sensitivity is achieved. The dual-mode method not only demonstrates outstanding properties and practicability, but also presents an effective, highly efficient and reliable method for detecting PCT.

Ultrasound assisted electrodeposition of photocatalytic antibacterial MoS2-Zn coatings controlled by sodium dodecyl sulfate.

Photocatalytic MoS2 with visible light response is considered as a promising bactericidal material owing to its non-toxicity and high antibacterial efficiency. However, photocatalysts always exist as powder, so it is difficult to settle photocatalysts on the metal surface, which limits their application in aqueous environments. To solve this problem, ultrasound and sodium dodecyl sulfate (SDS) were introduced into the co-deposition process of MoS2 and zinc matrix, so that novel MoS2-Zn coatings were obtained. In this process, ultrasound and SDS strongly promoted the dispersion and adsorption of MoS2 on the co-depositing surfaces. Then MoS2 were proved to be composited into the Zn matrix with effective structures, and the addition of SDS effectively increased the loading content of MoS2 in the MoS2-Zn coatings. Besides, the antibacterial performance of the MoS2-Zn coatings was evaluated with three typical fouling bacteria E.coli, S.aureus and B.wiedmannii. The MoS2-Zn coating showed high and broad-spectrum antibacterial properties with over 98 % inhibition rate against these three bacteria. Furthermore, it is proved that the MoS2-Zn coatings generated superoxide (·O2-) and hydroxyl radicals (·OH) under visible light, which played the dominant and subordinate roles in the antibacterial process, respectively. The MoS2-Zn coatings also showed high antibacterial stability after four "light-dark" cycles. According to the results of the attached bacteria, the MoS2-Zn coatings were considered to effectively repel the living pelagic bacteria instead of killing the attached ones, which was highly environmentally friendly. The obtained MoS2-Zn coatings were considered promising in biofilm inhibiting and marine antifouling fields.

Aptamer-based flares hybridized with single-stranded DNA-conjugated MoS2 nanosheets for ratiometric fluorescence sensing and imaging of potassium ions and adenosine triphosphate in human fluids and living cells.

Addressing the limitations observed in previous studies, where the quantitative range of nanoprobes for detecting K+ and adenosine triphosphate (ATP) did not cover concentrations found within living cells, the present study aimed to develop ratiometric nanoprobes that can accurately sense changes in K+ and ATP levels in living cells and quantify them in human fluids. The proposed nanoprobes consisted of recognition flares modified with 6-carboxyfluorescein (FAM) and 5-carboxytetramethylrhodamine (TAMRA), along with thiolate single-stranded DNA (ssDNA) and molybdenum disulfide nanosheets (MoS2 NSs). The thiolate ssDNA acts as a linker between the flares and the MoS2 NSs, directly forming a functional nanostructure at room temperature. The direct conjugation of labeled flares to the MoS2 NSs simplifies the fabrication process. In the absence of K+ and ATP, the hybridization of flares and thiolate ssDNA caused FAM to move away from TAMRA, suppressing the fluorescence resonance energy transfer (FRET) process. However, upon the introduction of K+ and ATP, the flares undergo a structural transformation via the formation of G-quadruplex formation and the generation of hairpin-shaped structures, respectively. This structural change leads to the release of the flares from the ssDNA-conjugated nanosheet surface. The release of the flares brings FAM and TAMRA into close proximity, allowing FRET to occur, leading to FRET and static quenching. By monitoring the ratio between the fluorescence intensities of FAM and TAMRA, the concentration of K+ (5-100 mM) and ATP (0.3-5 mM) can be accurately determined by the proposed nanoprobes. The advantages of these nanoprobes lie in their ability to provide ratiometric measurements, which enhance the accuracy and reliability of the quantification process. The proposed nanoprobes offer potential applications as ratiometric imaging probes for monitoring K+ and ATP-related reactions in living cells, providing valuable insights into cellular processes. Additionally, they can be employed for determining the levels of K+ and ATP in human fluids, offering potential diagnostic applications in various clinical settings.