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Mucus is a hydrated, viscoelastic, and adhesive gel that lubricates and protects the body from pathogens; however, its protective function hinders drug/nanomedicine diffusion and treatment efficiency. Therefore, novel drug delivery strategies are required to overcome challenging mucosal barriers. Here, multi-responsive nanogels (NGs) are developed and explored their interaction with mucus. Specific NG features (e.g., surface charge, temperature responsiveness, and redox response) are evaluated in a typical mucus-associated environment (i.e., mucin proteins and high glutathione concentrations). The results demonstrate that biocompatibility and the capacity to deliver a protein through mucosal barriers in different in vitro and in vivo models highlight the importance of specific NG design elements. Disulfide bonds are highlighted as redox-sensitive cross-linkers within the NG structure as critical for drug delivery performance; they function as degradation points that enable NG degradation and subsequent drug release and anchoring points to adhere to mucin, thereby enhancing their residence time at the desired site of action. Additionally, it is confirmed that surface charges impact interactions with mucin; positively charged NGs exhibit improved interactions with mucin compared to negatively charged and neutral NGs. Overall, the findings underline the importance of redox response and surface charge in NG design for reaching efficient mucosal drug delivery.  相似文献   

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The trade-off between the responsivity and response speed is a key limiting factor for the realization of high-performance photodetectors. Here, a core–shell single-nanowire structure with radial carrier transport is proposed for the possibility of breaking this trade-off. Taking multilayer molybdenum disulfide (MoS2) as the exemplified material, the photoelectric responses of the core–shell nanowire MoS2 photodetector are theoretically predicted and numerically simulated. Thanks to the enhanced light absorptivity and ultra-short transmission distance of carriers in the nanowire, the photodetector achieves an ultrahigh responsivity with sustaining a short response time. In a wide range of visible spectrum, the responsivity, response time, and specific detectivity of the nanowire photodetector reach 104 A W−1, 230 ps, and 1012 Jones, respectively, according to the optoelectronic simulation. The responsivity-bandwidth product is predicted up to ≈1013 Hz A W−1, which is at least three orders of magnitude higher than that of the conventional MoS2-based photodetectors. It is believed that the nanowire design provides a new scheme for promoting the development of the high-performance photodetectors.  相似文献   

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2D transition metal dichalcogenide MoS2 nanosheets are increasingly attracting interests due to their promising applications in materials science and biomedicine. However, their biocompatibility and their biodegradability have not been thoroughly studied yet. Here, the biodegradability of exfoliated pristine and covalently functionalized MoS2 (f ‐MoS2) is investigated. First, biodegradability of these nanomaterials is evaluated using plant horseradish peroxidase and human myeloperoxidase. The results reveal that the enzymatic degradability rate of MoS2 and f ‐MoS2 is slower than in the case of the simple treatment with H2O2 alone. In parallel, high biocompatibility of both pristine and f ‐MoS2 nanosheets is found up to 100 µg mL?1 in both cell lines (HeLa and Raw264.7) and primary immune cells. In addition, no immune cell activation and minimal pro‐inflammatory cytokine release are observed in RAW264.7 and human monocyte‐derived macrophages, suggesting a negligible cellular impact of such materials. Furthermore, the effects of degraded MoS2 and partially degraded f‐ MoS2 products on cell viability and activation are studied in cancer and immune cells. A certain cytotoxicity is measured at the highest concentrations. Finally, to prove that the cellular impact is due to cell uptake, the internalization of both pristine and functionalized MoS2 in cancer and primary immune cells is assessed.  相似文献   

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The potassium‐ion battery (PIB) is an attractive energy storage device that possesses the potential advantages of high energy density and low cost. Herein, a pure 1T‐MoS2 is synthesized on graphene oxide and assembled into a hydrogel. The hydrogel is further tightened to a compact 1T‐MoS2/graphene (CTMG) bulk by a densifying strategy of capillary tension. When employed as an anode for PIBs, the CTMG electrode can store K+ through reversible intercalation and conversion electrochemistry, accompanied with fast kinetics since the 1T‐MoS2 induces a pseudocapacitive storage mechanism and the extraordinary K+ transportation ability. Consequently, the CTMG electrode delivers the high and reversible rate capacities of 511 and 327 mAh g‐1 at 0.1 and 1 A g‐1, respectively. Moreover, the compact architecture reduces the electrode thickness by ≈33% enabling a high volumetric capacity (512 mAh cm‐3 at 0.1 A g‐1 after 100 cycles), as well as holding a promising application in thick electrode.  相似文献   

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Photosensitizers (PSs) are light‐sensitive molecules that are highly hydrophobic, which poses a challenge to their use for targeted photodynamic therapy. Hence, considerable efforts have been made to develop carriers for the delivery of PSs. Herein, a novel design is described of highly biocompatible, fluorescent, folic acid (FA)‐functionalized carbon nanodots (CDs) as carriers for the PS zinc phthalocyanine (ZnPc) to achieve simultaneous biological imaging and targeted photodynamic therapy. FA is modified on PEG‐­passivated CDs (CD‐PEG) for targeted delivery to FA‐positive cancer cells, and ZnPc is loaded onto CD‐PEG‐FA via π–π stacking interactions. CD‐PEG‐FA/ZnPc exhibits excellent targeted delivery of the PS, leading to simultaneous imaging and significant targeted photodynamic therapy after irradiation in vitro and in vivo. The present CD‐based targeted delivery of PSs is anticipated to offer a convenient and effective platform for enhanced photodynamic therapy to treat cancers in the near future.  相似文献   

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Ti‐doped MoS2 nanotubes are produced by pyrolyzing a H2S/N2 mixture over an oxidized Ti–Mo alloy powder at elevated temperatures. Partial substitution of Mo by Ti does not significantly alter the 2H–MoS2 lattice.  相似文献   

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The tuning of charge carrier concentrations in semiconductor is necessary in order to approach high performance of the electronic and optoelectronic devices. It is demonstrated that the charge‐carrier density of single‐layer (SL), bilayer (BL), and few‐layer (FL) MoS2 nanosheets can be finely and reversibly tuned with N2 and O2 gas in the presence of deep‐ultraviolet (DUV) light. After exposure to N2 gas in the presence of DUV light, the threshold voltages of SL, BL, and FL MoS2 field‐effect transistors (FETs) shift towards negative gate voltages. The exposure to N2 gas in the presence of DUV light notably improves the drain‐to‐source current, carrier density, and charge‐carrier mobility for SL, BL, and FL MoS2 FETs. Subsequently, the same devices are exposed to O2 gas in the presence of DUV light for different periods and the electrical characteristics are completely recovered after a certain time. The doping by using the combination of N2 and O2 gas with DUV light provides a stable, effective, and facile approach for improving the performance of MoS2 electronic devices.  相似文献   

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Coupling between non‐toxic lead‐free high‐k materials and 2D semiconductors is achieved to develop low voltage field effect transistors (FETs) and ferroelectric non‐volatile memory transistors as well. In fact, low voltage switching ferroelectric memory devices are extremely rare in 2D electronics. Now, both low voltage operation and ferroelectric memory function have been successfully demonstrated in 2D‐like thin MoS2 channel FET with lead‐free high‐k dielectric BaxSr1‐xTiO3 (BST) oxides. When the BST surface is coated with a 5.5‐nm‐ultrathin poly(methyl methacrylate) (PMMA)‐brush for improved roughness, the MoS2 FET with BST (x = 0.5) dielectric results in an extremely low voltage operation at 0.5 V. Moreover, the BST with an increased Ba composition (x = 0.8) induces quite good ferroelectric memory properties despite the existence of the ultrathin PMMA layer, well switching the MoS2 FET channel states in a non‐volatile manner with a ±3 V low voltage pulse. Since the employed high‐k dielectric and ferroelectric oxides are lead‐free in particular, the approaches for applying high‐k BST gate oxide for 2D MoS2 FET are not only novel but also practical towards future low voltage nanoelectronics and green technology.  相似文献   

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2D materials, specifically MoS2 semiconductors, have received tremendous attention for photo‐sensing applications due to their tunable bandgap and low noise levels. A unique photodetector using multilayer MoS2 as the semiconductor channel, in which the gate electrode of the device is permanently connected to the grounded source electrode to introduce rectification, is reported. The proposed grounded‐gate photodiode exhibits high photoresponsivity of 1.031 A W−1, excellent photodetectivity (>6 × 1010 jones), and highly stable rise/fall time response (100–200 ms) under illumination of visible light (at the wavelengths of 405, 532, and 638 nm). Numerical device simulations using quantum transport methods and photoconductive effects are used to explain the device operation. It is also suggested that the gate metal work function can be carefully chosen to increase the sensitivity of the grounded‐gate photodetector by suppressing the dark current. The grounded‐gate device proposed, owing to the properties of rectifying behavior, low contact resistance, consistent photoresponsivity, and linear sensitivity, provides a new platform for next‐generation applications in the field of electronics and optoelectronics.  相似文献   

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The first utilization of nitrogen‐doped graphdiyne (NGDY) as an efficient catalytic promoter for hydrogen evolution reaction (HER) is reported. X‐ray powder diffraction and X‐ray photoelectron spectroscopy studies indicate the presence of strong interactions between NGDY and MoS2, which should effectively facilitate the charge transport behavior and improvement of the HER kinetics. The creative hybridization of MoS2 and NGDY endows such heterostructure with structural and compositional advantages for boosting the catalytic activity (low overpotential of 186 mV at 10 mA cm?2 and Tafel slope of 63 mV dec?1) and extraordinary stability (higher than all reported MoS2‐based materials and even better than that of commercial Pt and almost all benchmarked electrocatalysts). All of the results not only demonstrate that NGDY can be used as an effective catalytic promoter for hydrogen production, but also provide new strategy for fabricating efficient water‐splitting electrodes.  相似文献   

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Smart drug delivery systems with on‐demand drug release capability are rather attractive to realize highly specific cancer treatment. Herein, a novel light‐responsive drug delivery platform based on photosensitizer chlorin e6 (Ce6) doped mesoporous silica nanorods (CMSNRs) is developed for on‐demand light‐triggered drug release. In this design, CMSNRs are coated with bovine serum albumin (BSA) via a singlet oxygen (SO)‐sensitive bis‐(alkylthio)alkene (BATA) linker, and then modified with polyethylene glycol (PEG). The obtained CMSNR‐BATA‐BSA‐PEG, namely CMSNR‐B‐PEG, could act as a drug delivery carrier to load with either small drug molecules such as doxorubicin (DOX), or larger macromolecules such as cis‐Pt (IV) pre‐drug conjugated third generation dendrimer (G3‐Pt), both of which are sealed inside the mesoporous structure of nanorods by BSA coating. Upon 660 nm light irradiation with a rather low power density, CMSNRs with intrinsic Ce6 doping would generate SO to cleave BATA linker, inducing detachment of BSA‐PEG from the nanorod surface and thus triggering release of loaded DOX or G3‐Pt. As evidenced by both in vitro and in vivo experiments, such CMSNR‐B‐PEG with either DOX or G3‐Pt loading offers remarkable synergistic therapeutic effects in cancer treatment, owing to the on‐demand release of therapeutics specifically in the tumor under light irradiation.  相似文献   

14.
Effective on-demand release of therapeutics at an intracellular drug supply hub, the cytosol, is among the important steps for successful drug delivery. To improve cytosolic drug release, this study selects diselenide because the bond is cleaved by both glutathione (GSH) and reactive oxygen species (ROS) in the cytosol. Specifically, upon diselenide cleavage, the levels of GSH or ROS are reduced, resulting in decreased or increased cell viability and either the synergistic or antagonistic death of cancer cells with an anticancer drug, respectively, because GSH and ROS trigger two conflicting functions (i.e., antioxidant vs prooxidant activity). Thus, this study designs a diselenide-based drug carrier to determine which trigger is the major cause of diselenide degradation, how the disrupted balance between GSH and ROS levels influences cell viability and drug efficacy, and whether the combined use of a diselenide drug carrier and a drug has a synergistic or antagonistic effect. Using a multiple diselenide-containing nanoparticle (MSePCL-NP), the study shows that diselenide is cleaved to a greater extent by GSH than by ROS; MSePCL-NP induces a greater decrease in the viability of cancer cells, but not normal cells; a combination of DOX@MSePCL-NP synergistically kills cancer cells and inhibits tumor growth in vivo.  相似文献   

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Exploring TiO2‐photocatalysts for sunlight conversion has high demand in artificial photosynthesis. In this work, edge‐enriched ultrathin molybdenum disulfide (MoS2) flakes are uniformly embedded into the bulk of yolk‐shell TiO2 as a cocatalyst to accelerate photogenerated‐electron transfer from the bulk to the surface of TiO2. The as‐formed MoS2/TiO2 (0.14 wt%) hybrids exhibit a high hydrogen evolution rate (HER) of 2443 µmol g?1 h?1, about 1000% and 470% of that of pristine TiO2 (247 µmol g?1 h?1) and bulk MoS2 decorated TiO2 (513 µmol g?1 h?1). Such a greatly enhanced HER is attributed to the exposed catalytic edges of the ultrathin MoS2 flakes with a robust chemical linkage (Ti? S bond), providing rapid charge transfer channels between TiO2 and MoS2. The catalytic stability is promoted by the antiaggregation of the highly dispersed MoS2 flakes in the bulk of yolk‐shell TiO2. The exponential fitted decay kinetics of time‐resolved photoluminescence (ns‐PL) spectra illustrates that embedding ultrathin MoS2 flakes in TiO2 effectively decreases the average lifetime of PL in the MoS2/TiO2 hybrids (τave = 4.55 ns), faster than that of pristine TiO2 (≈7.17 ns) and the bulk MoS2/TiO2 (≈6.13 ns), allowing a superior charge separation and charge trapping process for reducing water.  相似文献   

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Seeking controllable and efficient surface dopant molecules for transition‐metal dichalcogenides (TMDCs) is highly valuable for fully understanding TMDCs properties and their applications to relevant devices. The general doping effect of solvents on TMDCs are explored. By selecting suitable solvents with optimized relevant factors, controllable n‐doping of molybdenum disulfide (MoS2) is obtained on the same device with the sheet density of electrons increased from 2.3 × 1011 to 6.4 × 1012, 9.7 × 1012, and 1.6 × 1013 by use of dimethylsulfoxide, N,N‐dimethylformamide, and N‐methyl‐pyrrolidone (NMP), respectively. The doping principle is explained by charge‐donating characteristics of molecule and dipole interaction. After doping by NMP, the contact resistance is reduced by four times, and the on/off current ratio of fabricated top‐gated MoS2 transistors is increased by 3 orders of magnitude. This work can guide the selection of suitable solvents for effective doping of two‐dimensional materials and advance the development of precise controllable electronic and optoelectronic devices.  相似文献   

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Dendritic patterns generated in non‐equilibrium growth processes are prevalent in nature while their formation mechanisms are far from fully understood. Here, we report a coverage‐dependent fractal degree evolution of monolayer 2H‐MoS2 dendrites synthesized on a symmetry‐disparate substrate of SrTiO3 (001). Surprisingly, various characterizations have revealed that the monolayer dendrites featured with orthogonal backbones are single crystalline, possessing both peculiar adlayer‐substrate interaction and abnormal indirect bandgap on SrTiO3 (001). Further theoretical calculations indicate that a prominent diffusion anisotropy of monomer precursors, combined with the disparate adlayer‐substrate symmetry, determine the diffusion‐limited aggregation of MoS2 towards dendritic shapes. This work provides brand‐new insights in the morphological engineering of two‐dimensional atomic crystals, and contributes greatly to an in‐depth understanding of the detailed dynamics in non‐equilibrium crystal growth.  相似文献   

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Precise modulation of electrical and optical properties of 2D transition metal dichalcogenides (TMDs) is required for their application to high‐performance devices. Although conventional plasma‐based doping methods have provided excellent controllability and reproducibility for bulk or relatively thick TMDs, the application of plasma doping for ultrathin few‐layer TMDs has been hindered by serious degradation of their properties. Herein, a reliable and universal doping route is reported for few‐layer TMDs by employing surface‐shielding nanostructures during a plasma‐doping process. It is shown that the surface‐protection oxidized polydimethylsiloxane nanostructures obtained from the sub‐20 nm self‐assembly of Si‐containing block copolymers can preserve the integrity of 2D TMDs and maintain high mobility while affording extensive control over the doping level. For example, the self‐assembled nanostructures form periodically arranged plasma‐blocking and plasma‐accepting nanoscale regions for realizing modulated plasma doping on few‐layer MoS2, controlling the n‐doping level of few‐layer MoS2 from 1.9 × 1011 cm?2 to 8.1 × 1011 cm?2 via the local generation of extra sulfur vacancies without compromising the carrier mobility.  相似文献   

19.
纳米二硫化钼的制备与表征   总被引：6，自引：0，他引：6  
本文采用超音速气流粉碎机对二硫化钼(MoS2)粉体进行粉碎，从而得到纳米二硫化钼。XRD分析结果显示MoS2晶体结构在粉碎过程中未发生转变；SEM分析结果显示粉碎后MoS2粉体粒径明显变小，剥离后得到MoS2片层厚度为30-50nm。  相似文献   

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One of the major challenges in medicine is the delivery and control of drug release over time. Current approaches take advantage of mesostructured silica nanoparticles (MSNs) as carriers but suffer several problems including complex synthesis that requires sequential steps for (1) removal of surfactants and (2) functionalization of MSNs to allow upload of the drugs. Here, a novel solution is presented to these restrictions: the design of drug‐structure‐directing agents (DSDAs) with dual inherent pharmacological activity and ability to direct the formation of solid and hollow‐shell MSNs. Pharmacologically active DSDAs obtained by amidation of drugs with fatty acids are allowed to form micelles, around which the inorganic species self‐assembled to form MSNs. Since the DSDAs direct the formation of MSNs, the steps to remove surfactants, functionalization, and drug upload are not required. The MSNs thus prepared provide sustained release of the drug over more than six months, as well as rapid cellular internalization by both physiological and tumoral human colon cells without affecting cell viability. Moreover, the gradual intracellular release of both, the active drug and lipid moiety with potential nutraceutical properties is proved. MSN particles designed with this approach are promising vehicles for controlled and sustained intra‐or extracellular drug‐delivery.  相似文献   

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