Query: Molybdenum Disulfide Quantum Dots 

title: Simple hydrothermal approach for synthesis of fluorescent molybdenum disulfide quantum dots: Sensing of Cr3+ ion and cellular imaging.
abstract: Nowadays, fluorescent molybdenum disulfide quantum dots (MoS2 QDs) have proven to be potential candidates in the sensing and bioimaging areas owing to their exceptional intrinsic characteristics. Here, a simple hydrothermal strategy was explored for the preparation of MoS2 QDs using ammonium heptamolybdate and 6 mercaptopurine (6 MP) as precursors. The emission peak of MoS2 QDs was significantly quenched in the presence Cr3+ ion due to the selective surface chemistry on the surfaces of MoS2 QDs. The designed fluorescent MoS2 QDs showed a linear fluorescence quenching response with increasing concentration of Cr3+ ion (0.1 10 mM) allowing to detect Cr3+ ion even at 0.08 mM. This fluorescent MoS2 QDs were utilized for the quantification of Cr3+ ion in real samples (water and biological samples) Interestingly, the synthesized MoS2 QDs exhibited negligible cytotoxicity on NRK cells and acted as good candidates for imaging of Trichoderma viride fungal cells.

title: Preparation and evaluation of a molybdenum disulfide quantum dots embedded C18 mixed mode chromatographic stationary phase
abstract: Molybdenum disulfide quantum dots (MoS 2 QDs) were chosen as a functional two dimensional material to improve the separation performance of a traditional C18 column. In this work, MoS 2 QDs were synthesized by the combination of sonication and solvothermal treatment of bulk MoS 2 The prepared MoS 2 QDs were characterized by transmission electron microscope (TEM) Zeta potential measurement, UV visible absorption and fluorescence spectroscopy. Then, a novel MoS 2 QDs embedded C18 (Sil MoS 2 C18) stationary phase was prepared for performing mixed mode liquid chromatography. The results of elemental analysis (EA) thermogravimetric analysis (TGA) Fourier transform infrared spectrometry (FT IR) X ray photoelectron spectroscopy (XPS) scanning electron microscope (SEM) and Brunauer Emmett Teller (BET) measurements indicated the stationary phase was prepared successfully. Five types of compounds including alkylbenzenes, polycyclic aromatic hydrocarbons (PAHs) nucleosides and nucleobases, anilines and flavonoids were utilized to evaluate reversed phase, weak cation exchange and hydrophilic interaction of the new column. To a certain extent, the column could achieve separation for different properties of samples on one column, with less organic solvent and shorter time than conventional alkyl and amino columns. Furthermore, the mechanism for separation was studied by investigating effects of mobile phase composition and pH on retentions. In summary, the Sil MoS 2 C18 stationary phase was deemed able to serve the performance of various types of phases, which revealed the prepared mixed mode column could be potentially applied for the analysis of complex samples.

title: Synthesis of Tungsten Disulfide and Molybdenum Disulfide Quantum Dots and Their Applications
abstract: With fascinating optical, electronic, and mechanical properties, tungsten disulfide (WS2) and molybdenum disulfide (MoS2) quantum dots (QDs) are promising for related applications. Their bandgap en.

title: Facile preparation of molybdenum disulfide quantum dots using a femtosecond laser
abstract: Molybdenum disulfide (MoS2) is rapidly emerging in a wide range of applications owing to its superior optical, electrical, and catalytic properties. In particular, aside from the current great interest in monolayer MoS2, MoS2 quantum dots (QDs) have received much attention in the electronics and optoelectronics fields owing to their inherent electrical and optical properties arising from the quantum confinement effect. Thus, various methods for producing MoS2 QDs, such as exfoliation, substrate growth, and colloidal synthesis, have been attempted. In this study, the method for manufacturing MoS2 QD with a size of 10 nm which is simpler than the conventional method was devised. On the basis of characterization of the prepared MoS2 QD samples, resistive switching devices was fabricated. These devices demonstrated stable unipolar resistive switching behavior without an electroforming process. This study provides a new approach for the mass production of MoS2 QD and one of their potential applications.

title: Photogenerated Charge Carriers in Molybdenum Disulfide Quantum Dots with Enhanced Antibacterial Activity.
abstract: Molybdenum disulfide (MoS2) nanosheets have received considerable interest due to their superior physicochemical performances to graphene nanosheets. As the lateral size and layer thickness decrease, the formed MoS2 quantum dots (QDs) show more promise as photocatalysts, endowing them with potential antimicrobial properties under environmental conditions. However, studies on the antibacterial photodynamic therapy of MoS2 QDs have rarely been reported. Here, we show that MoS2 QDs more effectively promote the creation and separation of electron hole pair than MoS2 nanosheets, resulting in the formation of multiple reactive oxygen species (ROS) under simulated solar light irradiation. As a result, photoexcited MoS2 QDs show remarkably enhanced antibacterial activity, and the ROS mediated oxidative stress plays a dominant role in the antibacterial mechanism. The in vivo experiments showed that MoS2 QDs are efficacious in wound healing under simulated solar light irradiation and exert protective effects on normal tissues, suggesting good biocompatibility properties. Our findings provide a full description of the photochemical behavior of MoS2 QDs and the resulting antibacterial activity, which might advance the development of MoS2 based nanomaterials as photodynamic antibacterial agents under environmental conditions.

title: A molybdenum disulfide quantum dots based ratiometric fluorescence strategy for sensitive detection of epinephrine and ascorbic acid.
abstract: In this paper, a novel and sensitive ratiometric fluorescence strategy for the detection of epinephrine (EP) and ascorbic acid (AA) was established based on the fluorescence resonance energy transfer (FRET) between the molybdenum disulfide quantum dots (MQDs) and the fluorescent oxidative polymerization product (PEP PEI) of EP in polyethyleneimine (PEI) aqueous solution. The continuous formation of PEP PEI can lead to the fluorescence quenching of MQDs at 414 nm while the fluorescence of PEP PEI at 522 nm gradually increased. The introduction of AA can inhibit the oxidative polymerization process of EP due to the strong reducibility of AA, resulting in the fluorescence recovery of MQDs at 414 nm and the fluorescence decreasing of PEP PEI at 522 nm. Therefore, EP and AA can be monitored by measuring the ratio of the fluorescence intensities at 522 nm and 414 nm. A good linear calibration of I522/I414 versus EP and AA concentrations were obtained within 0.2 40 mM and 0.5 40 mM, respectively. And the detection limit was 0.05 mM for EP and 0.2 mM for AA. Furthermore, the developed ratiometric fluorescence method with high sensitivity and selectivity was applied for EP in human urine samples and AA in human serum samples determination with satisfactory results obtained.

title: Molybdenum disulfide quantum dots directing zinc indium sulfide heterostructures for enhanced visible light hydrogen production.
abstract: Photocatalytic hydrogen (H2) production based on semiconductors is important to utilize solar light for clean energy and environment. Herein, we report a visible light responsive heterostructure, designed and constructed by molybdenum disulfide quantum dots (MoS2 QDs) in situ seeds directing growth and self assemble of zinc indium sulfide (ZnIn2S4) nanosheet to ensure their full contact through a simple one step solvothermal method for highly improved visible light H2 production. The MoS2 QDs in situ seeds directing ZnIn2S4 heterostructure not only builds heterojunctions between MoS2 and ZnIn2S4 to spatially separate the photogenerated electrons and holes, but also serves as the active sites trapping photogenerated electrons to facilitate H2 evolution. As a result, MoS2 QDs/ZnIn2S4 exhibits high photocatalytic activity for H2 production, and the optimized 2 wt% MoS2 QDs/ZnIn2S4 (2MoS2 QDs/ZnIn2S4) heterostructure exhibits the highest H2 evolution rate of 7152 umol*h 1*g 1 under visible light, ~9 times of pure ZnIn2S4. Our strategy here could shed some lights on developing noble metal free heterostructures for highly efficient photocatalytic H2 production.

title: Boronic acid functionalized molybdenum disulfide quantum dots for the ultrasensitive analysis of dopamine based on synergistic quenching effects from IFE and aggregation.
abstract: Herein, a novel fluorescent material, boronic acid functionalized molybdenum disulfide quantum dots (B MoS2 QDs) produced by an amidation reaction between 3 aminobenzeneboronic acid and previously prepared molybdenum disulfide quantum dots (MoS2 QDs) was prepared to fabricate a rapid and sensitive platform for the quantitative analysis of dopamine. This material exhibits strong fluorescence, excellent salt tolerance and light fastness. In particular, the quantum yield of this material is about 21.1 times that of its fundamental material, MoS2 QDs. Notably, owing to an interesting synergistic effect between the inner filter effect and the aggregation quenching effect, this material was successfully applied for the determination of dopamine in the linear range 0.25 35 mmol L 1 with the detection limit of 0.087 mmol L 1; moreover, B MoS2 QDs manifested better selectivity in the presence of multiple interferences due to their inert surface. As expected, this proposed material shows satisfactory performance in human serum; thus, the present study exploits a new avenue for the application of functionalized MoS2 QDs in fluorescence sensing.

title: A double signal nanoprobe based on molybdenum disulfide quantum dots/manganese dioxide nanosheets for glutathione detection
abstract: In this study, we established a novel double signal nanoprobe (fluorometric and colorimetric method) for the detection of Glutathione (GSH) using molybdenum disulfide quantum dots/manganese dioxide nanosheets (MoS2 QDs/MnO2) As for the nanoprobe, the fluorescence of MoS2 QDs was quenched by MnO2 nanosheets via the inner filter effect and static quenching effect, after adding GSH to the MoS2 QDs/MnO2 solution, both the color and fluorescence of the solution change dramatically due to the reduction of MnO2 to Mn2+ by GSH. By measuring the changes of the fluorescence of MoS2 QDs and the ultraviolet absorption of MnO2 of the solution with respect to GSH concentrations, the linear range for the detection of GSH was obtained (5.0 to 300.0 mM for fluorometric assay; 2.0 to 300.0 mM for colorimetric assay) The detection limit is 1.57 mmol*L 1 for the fluorescence method, and 0.50 mmol*L 1 for colorimetric method, respectively.

title: Molybdenum Disulfide Quantum Dots Attenuates Endothelial to Mesenchymal Transition by Activating TFEB Mediated Lysosomal Biogenesis.
abstract: A defective lysosome autophagy degradation pathway contributes to a variety of endothelial to mesenchymal transition (EndMT) related cardiovascular diseases. Molybdenum disulfide quantum dots (MoS2 QDs) are nanoscale sizes in the planar dimensions and atomic structures of transition metal dichalcogenides (TMDs) materials with excellent physicochemical and biological properties, making them ideal for various biomedical applications. In this study, water soluble MoS2 QDs with an average diameter of about 3.4 nm were synthesized by using a sulfuric acid assisted ultrasonic method. The as prepared MoS2 QDs exhibited low cytotoxicity of less than 100 mg/mL in both human umbilical vein endothelial cells and human coronary artery endothelial cells and showed novel biological properties to prevent EndMT and promote angiogenesis in vitro. We found that MoS2 QDs treatment induced transcription factor (TFEB) mediated lysosomal biogenesis, which could cause autophagy activation. Importantly, using in vitro transforming growth factor (TGF) b induced EndMT model, we demonstrated that the cardiovascular protective effect of MoS2 QDs against EndMT acted through triggering TFEB nucleus translocation and restoring an impairment of autophagic flux, whereas genetic suppression of TFEB impaired the protective action of MoS2 QDs against EndMT. Taken together, these results gain novel insights into the mechanisms by which MoS2 QDs regulate EndMT and facilitate the development of MoS2 based nanoagents for the treatment of EndMT related cardiovascular diseases.