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Two-dimensional van der Waals heterostructures (vdWHs) have attracted considerable interest.sup.1-4. However, most vdWHs reported so far are created by an arduous micromechanical exfoliation and manual restacking process.sup.5, which--although versatile for proof-of-concept demonstrations.sup.6-16 and fundamental studies.sup.17-30--is clearly not scalable for practical technologies. Here we report a general synthetic strategy for two-dimensional vdWH arrays between metallic transition-metal dichalcogenides (m-TMDs) and semiconducting TMDs (s-TMDs). By selectively patterning nucleation sites on monolayer or bilayer s-TMDs, we precisely control the nucleation and growth of diverse m-TMDs with designable periodic arrangements and tunable lateral dimensions at the predesignated spatial locations, producing a series of vdWH arrays, including VSe.sub.2/WSe.sub.2, NiTe.sub.2/WSe.sub.2, CoTe.sub.2/WSe.sub.2, NbTe.sub.2/WSe.sub.2, VS.sub.2/WSe.sub.2, VSe.sub.2/MoS.sub.2 and VSe.sub.2/WS.sub.2. Systematic scanning transmission electron microscopy studies reveal nearly ideal vdW interfaces with widely tunable moiré superlattices. With the atomically clean vdW interface, we further show that the m-TMDs function as highly reliable synthetic vdW contacts for the underlying WSe.sub.2 with excellent device performance and yield, delivering a high ON-current density of up to 900 microamperes per micrometre in bilayer WSe.sub.2 transistors. This general synthesis of diverse two-dimensional vdWH arrays provides a versatile material platform for exploring exotic physics and promises a scalable pathway to high-performance devices. A general strategy for the synthesis of two-dimensional van der Waals heterostructure arrays is used to produce high-performance electronic devices, showing the potential of this scalable approach for practical technologies., Author(s): Jia Li [sup.1] , Xiangdong Yang [sup.1] , Yang Liu [sup.2] , Bolong Huang [sup.3] , Ruixia Wu [sup.1] , Zhengwei Zhang [sup.1] , Bei Zhao [sup.1] , Huifang [...]

Exploring the dynamic structural evolution of electrocatalysts during reactions represents a fundamental objective in the realm of electrocatalytic mechanism research. In pursuit of this objective, we synthesized PhenPtCl2 nanosheets, revealing a N2-Pt-Cl2 coordination structure through various characterization techniques. Remarkably, the electrocatalytic performance of these PhenPtCl2 nanosheets for hydrogen evolution reaction (HER) surpasses that of the commercial Pt/C catalyst across the entire pH range. Furthermore, our discovery of the dynamic coordination changes occurring in the N2-Pt-Cl2 active sites during the electrocatalytic process, as clarified through in situ Raman and X-ray photoelectron spectroscopy, is particularly noteworthy. These changes transition from Phen-Pt-Cl2 to Phen-Pt-Cl and ultimately to Phen-Pt. The Phen-Pt intermediate plays a pivotal role in the electrocatalytic HER, dynamically coordinating with Cl- ions in the electrolyte. Additionally, the unsaturated, two-coordinated Pt within Phen-Pt provides additional space and electrons to enhance both H+ adsorption and H2 evolution. This research illuminates the intricate dynamic coordination evolution and structural adaptability of PhenPtCl2 nanosheets, firmly establishing them as a promising candidate for efficient and tunable electrocatalysts. Exploring the dynamic structural evolution of electrocatalysts during electrochemical reactions is imperative. Here, the authors constructed 2D PhenPtCl2 nanosheets with Phen-Pt-Cl2 coordination structure which exhibit dynamic coordination evolution during hydrogen evolution reaction and good performance across the full pH range [ABSTRACT FROM AUTHOR]

The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single‐crystal perovskites (ABX3) are promising next‐generation materials for UV detection. The device performance of all‐inorganic CsPbCl3 photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer‐scale single‐crystal CsPbCl3 thin films are successfully grown by vapor‐phase epitaxy method, and the as‐constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 105, competitive responsivity of 32.8 A W−1, external quantum efficiency of 10867% and specific detectivity of 4.22 × 1012 Jones. More importantly, they feature superb long‐term stability toward moisture and oxygen within twenty‐one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated. [ABSTRACT FROM AUTHOR]

With the gradual depletion of traditional zinc resources, the full use of various non‐traditional zinc‐containing resources has received intensive attention. However, the efficient recovery of zinc ions with low concentrations remains challenging. Here efficient and continuous recovery of zinc ions in ammoniacal chloride media by a flat supported liquid membrane system is achieved, using Cyanex923 and TBP mixed extractant as the membrane phase. This article discusses the synergistic effect between Aliquat336, Cyanex923 and TBP, the effects of feed pH, total ammonia concentration, Cl− concentration and temperature on Zn(II) transport. [ABSTRACT FROM AUTHOR]

Single crystal metal halide perovskites thin films are considered to be a promising optical, optoelectronic materials with extraordinary performance due to their low defect densities. However, it is still difficult to achieve large‐scale perovskite single‐crystal thin films (SCTFs) with tunable bandgap by vapor‐phase deposition method. Herein, the synthesis of CsPbCl3(1–x)Br3x SCTFs with centimeter size (1 cm × 1 cm) via vapor‐phase deposition is reported. The Br composition of CsPbCl3(1–x)Br3x SCTFs can be gradually tuned from x = 0 to x = 1, leading the corresponding bandgap to change from 2.29 to 2.91 eV. Additionally, an low‐threshold (≈23.9 µJ cm−2) amplified spontaneous emission is achieved based on CsPbCl3(1–x)Br3x SCTFs at room temperature, and the wavelength is tuned from 432 to 547 nm by varying the Cl/Br ratio. Importantly, the high‐quality CsPbCl3(1–x)Br3x SCTFs are ideal optical gain medium with high gain up to 1369.8 ± 101.2 cm−1. This study not only provides a versatile method to fabricate high quality CsPbCl3(1–x)Br3x SCTFs with different Cl/Br ratio, but also paves the way for further research of color‐tunable perovskite lasing. [ABSTRACT FROM AUTHOR]

The increase of gate leakage current when the gate dielectric layer is thinned is a key issue for device scalability. For scaling down the integrated circuits, a thin gate dielectric layer with a low leakage current is essential. Currently, changing the dielectric layer material or enhancing the surface contact between the gate dielectric and the channel material is the most common way to reduce gate leakage current in devices. Herein, we report a technique of enhancing the surface contact between the gate dielectric and the metal electrode, that is constructing an Au/Al2O3/Si metalâ€"oxideâ€"semiconductor device by replacing the typical evaporated electrode/dielectric layer contact with a transferred electrode/high- Îş dielectric layer contact. The contact with a mild, non-invasive interface can ensure the intrinsic insulation of the dielectric layer. By applying 2â€"40 nm Al2O3 as the dielectric layer, the current densityâ€"electrical field (J â€" E) measurement reveals that the dielectric leakage generated by the transferred electrode is less than that obtained by the typical evaporated electrode with a ratio of 0.3 × 101 ∼ 5 × 106 at V bias = 1 V. Furthermore, at J  = 1 mA cmâˆ'2, the withstand voltage can be raised by 100â€"102 times over that of an evaporated electrode. The capacitanceâ€"voltage (C â€" V) test shows that the transferred metal electrode can efficiently scale the equivalent oxide layer thickness (EOT) to 1.58 nm, which is a relatively smaller value than the overall reported Si-based device’s EOT. This finding successfully illustrates that the transferred electrode/dielectric layer’s mild contact can balance the scaling of the gate dielectric layer with a minimal leakage current and constantly reduce the EOT. Our enhanced electrode/dielectric contact approach provides a straightforward and effective pathway for further scaling of devices in integrated circuits and significantly decreases the overall integrated circuit’s static power consumption (ICs). [ABSTRACT FROM AUTHOR]

Two-dimensional materials and their heterojunctions have received extensive attention in fundamental and applied research of photonics, electronics, and spintronics. Herein, we stacked SnS2, FePS3, and graphene (Gr) nanosheets into SnS2/FePS3/Gr van der Waals heterojunction, which exhibits broadband photoresponse from an ultraviolet region (405 nm) to an infrared region (850 nm) in atmosphere at room temperature. It was found that the dominated carrier of SnS2/FePS3 and SnS2/FePS3/Gr hererojunction was different in the electrical transport. The photoresponsivity of SnS2/FePS3/Gr heterojunction was about two orders of magnitude higher than that of SnS2 and FePS3 and SnS2/FePS3 heterojunction. The response time of SnS2/FePS3/Gr heterojunction was slightly shorter than that of SnS2/FePS3 heterojunction and two orders of magnitude shorter than that of SnS2 and FePS3 under the 450 nm laser. The high responsivity and short response time of SnS2/FePS3/Gr heterojunction should be attributed to the type II band alignment and short channel distance in the vertical direction where electrons and holes can be separated and transit fast. Our result offered an opportunity for realization of the high-performance and broadband photodetector. [ABSTRACT FROM AUTHOR]

A prerequisite for widespread applications of atomically thin transition metal dichalcogenides in future electronics is to achieve reliable electrical contacts, which is of considerable challenge due to the difficulties in selectively doping and inevitable physical damages of these atomically thin materials during typical metal integration process. Here, we report the in situ growth of ultrathin metallic NiSe single crystals on WSe2 in which the metallic NiSe nanosheets function as the contact electrodes to WSe2, creating an interface that is essentially free from chemical disorder. The NiSe/WSe2 heterostructures also exhibit well-aligned lattice orientation between the two layers, forming a periodic Moiré pattern. Electrical transport studies demonstrate that the NiSe nanosheets exhibit an excellent metallic feature, as evidenced by the extra-high electrical conductivity of up to 1.6×106 S·m−1. The WSe2 transistors with the NiSe contact show field-effect mobilities (μFE) more than double that with Cr/Au electrodes. This study demonstrates an effective pathway to achieve reliable electrical contacts to the atomically thin 2D materials, and maybe readily extended for fabricating 2D/2D low-resistance contacts for a variety of transition metal dichalcogenides. [ABSTRACT FROM AUTHOR]

The mixed-dimensional integration of two-dimensional (2D) materials with non-2D materials can give rise to prominent advances in performance or function. To date, the mixed-dimensional one-dimensional (1D)/2D heterostructures have been fabricated using various physical assembly approaches. However, direct epitaxial growth method which has notable advantages in preparing large-scale products and obtaining perfect interfaces is rarely investigated. Herein, we demonstrate for the first time the direct synthesis of the 1D/2D mixed-dimensional heterostructures by sequential vapor-phase growth of Sb2Se3 nanowires on WS2 monolayers. X-ray diffraction (XRD) pattern and Raman spectrum confirm the composition of the Sb2Se3/WS2 heterostructures. Transmission electron microscope (TEM) measurement demonstrates high quality of the heterostructures. Electrical transport characterization reveals that Sb2Se3 nanowire exhibits p-type characteristic and that WS2 monolayer exhibits n-type behavior, and that the p-n diode from 1D/2D mixed-dimensional Sb2Se3/WS2 heterostructure possesses obvious current rectification behavior. Optoelectronic measurements of the heterostructures show apparent photovoltaic response with an open-circuit voltage of 0.19 V, photoresponsivity of 1.51 A/W (Vds = 5 V) and fast response time of less than 8 ms. The van der Waals epitaxial growth mode of Sb2Se3 nanowires on WS2 monolayers is verified by stripping the Sb2Se3 nanowire from the heterostructures using tape. Together, the direct van der Waals epitaxy opens a facile pathway to 1D/2D mixed-dimensional heterostructures for functional electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals (vdWs) metal-semiconductor heterostructures with atomically sharp interface and matched work functions have recently attracted great attention due to their unique electronic and optoelectronic properties. Here we report the vapor phase epitaxial growth of large-scale vertical Sb/WSe2 metal-semiconductor vdWs heterostructures with uniform stacking orientation. Compared with the growth on SiO2/Si substrate, the thickness of Sb nanosheet on WSe2 can be reduced effectively to monolayer. We construct Sb-WSe2-Au asymmetric electrodes photodiode based on the Sb/WSe2 heterostructures. Electrical transport measurements indicate that the photodiode show obvious rectifying effect. Optoelectronic characterizations show prominent photoresponse with a high photoresposivity of 364 mA/W, a fast response time of less than 8 ms, a large open-circuit voltage of 0.27 V and a maximum electrical power output of 0.11 nW. The direct growth of high-quality metal-semiconductor vdWs heterostructures may open up new realms in 2D functional electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

• Simple synthesis 1D ZnS-CdS/TiO 2 rod/shell structure through successive ionic layer adsorption reaction. • Narrow band gap semiconductor CdS enhanced light absorption and utilization of photogenerated electrons of TiO 2. • ZnS passivation layer decrease loss of photogenerated electrons in photoanode film. Nano TiO 2 is a basic photoanode material in the application of new type solar cell for its appropriate bandgap and photoemission. However, traditionally TiO 2 -based photoanode films are limited in weak photoresponse and effortless recombination. Herein, we increase light absorption range through combined the uniform CdS quantum dots (QDs) by successive ionic layer adsorption reaction (SILAR) method and decrease the recombination of photo-generated electrons/holes through ZnS passivation layer overlaying on TiO 2 /CdS. Photocurrent response (i-t), photocurrent density-voltage (J-V) curves of TiO 2 /CdS/ZnS demonstrated the photovoltaic conversion efficiency (η) has been reaching 3.43%, which has 230% and 33% improvement than pure TiO 2 and TiO 2 /CdS. [ABSTRACT FROM AUTHOR]

2D metals have attracted considerable recent attention for their special physical properties, such as charge density waves, magnetism, and superconductivity. However, despite some recent efforts, the synthesis of ultrathin 2D metals nanosheets down to monolayer thickness remains a significant challenge. Herein, by using atomically flat 2D WSe2 or WS2 as the growth substrate, the synthesis of atomically thin 2D metallic MTe2 (M = V, Nb, Ta) single crystals with the thickness down to the monolayer regime and the creation of atomically thin MTe2/WSe2 (WS2) vertical heterojunctions is reported. Comparison with the growth on the SiO2/Si substrate under the same conditions reveals that the utilization of the dangling‐bond‐free WSe2 or WS2 as the van der Waals epitaxy substrates is crucial for the successful realization of atomically thin MTe2 (M = V, Nb, Ta) nanosheets. It is further shown that the epitaxial grown 2D metals can function as van der Waals contacts for 2D semiconductors with little interface damage and improved electronic performance. This study defines a robust van der Waals epitaxy pathway to ultrathin 2D metals, which is essential for fundamental studies and potential technological applications of this new class of materials at the 2D limit. Large‐domain‐size ultrathin MTe2 (M = V, Nb, Ta) nanoplates with the thickness down to the monolayer regime are prepared using 2D WSe2 or WS2 as the growth substrate. The atomically flat dangling‐bond‐free surface of WSe2 (WS2) ensures a minimized diffusion barrier for the successful realization of atomically thin 2D metallic MTe2 (M = V, Nb, Ta) nanosheets. [ABSTRACT FROM AUTHOR]

Tumor-associated macrophages (TAMs) are essential cellular components within tumor microenvironment (TME). TAMs are educated by TME to transform to M2 polarized population, showing a M2-like phenotype, IL-10high, IL-12low, TGF-βhigh. STAT3 signaling triggers crosstalk between tumor cells and TAMs, and is crucial for the regulation of malignant progression. In our study, legumain-targeting liposomal nanoparticles (NPs) encapsulating HC were employed to suppress STAT3 activity and “re-educate” TAMs, and to investigate the effects of suppression of tumor progression in vivo. The results showed that TAMs treated by HC encapsuled NPs could switch to M1-like phenotype, IL-10low, IL-12high, TGF-βlow, and the “re-educated” macrophages (M1-like macrophages) considerably demonstrated opposite effect of M2-like macrophages, especially the induction of 4T1 cells migration and invasion in vitro, and suppression of tumor growth, angiogenesis and metastasis in vivo. These data indicated that inhibition of STAT3 activity of TAMs by HC-NPs was able to reverse their phenotype and could regulate their crosstalk between tumor cells and TAMs in order to suppress tumor progression. [ABSTRACT FROM AUTHOR]

2D metals have attracted considerable recent attention for their special physical properties, such as charge density waves, magnetism, and superconductivity. However, despite some recent efforts, the synthesis of ultrathin 2D metals nanosheets down to monolayer thickness remains a significant challenge. Herein, by using atomically flat 2D WSe2 or WS2 as the growth substrate, the synthesis of atomically thin 2D metallic MTe2 (M = V, Nb, Ta) single crystals with the thickness down to the monolayer regime and the creation of atomically thin MTe2/WSe2 (WS2) vertical heterojunctions is reported. Comparison with the growth on the SiO2/Si substrate under the same conditions reveals that the utilization of the dangling‐bond‐free WSe2 or WS2 as the van der Waals epitaxy substrates is crucial for the successful realization of atomically thin MTe2 (M = V, Nb, Ta) nanosheets. It is further shown that the epitaxial grown 2D metals can function as van der Waals contacts for 2D semiconductors with little interface damage and improved electronic performance. This study defines a robust van der Waals epitaxy pathway to ultrathin 2D metals, which is essential for fundamental studies and potential technological applications of this new class of materials at the 2D limit. Large‐domain‐size ultrathin MTe2 (M = V, Nb, Ta) nanoplates with the thickness down to the monolayer regime are prepared using 2D WSe2 or WS2 as the growth substrate. The atomically flat dangling‐bond‐free surface of WSe2 (WS2) ensures a minimized diffusion barrier for the successful realization of atomically thin 2D metallic MTe2 (M = V, Nb, Ta) nanosheets. [ABSTRACT FROM AUTHOR]

Downsizing silicon-based transistors can result in lower power consumption, faster speeds, and greater computational capacity, although it is accompanied by the appearance of short-channel effects. The integration of high-mobility 2D semiconductor channels with ultrathin high dielectric constant (high-κ) dielectric in transistors is expected to suppress the effect. Nevertheless, the absence of a high-κ dielectric layer featuring an atomically smooth surface devoid of dangling bonds poses a significant obstacle in the advancement of 2D electronics. Here, ultrathin van der Waals (vdW) lanthanum oxychloride (LaOCl) dielectrics are successfully synthesized by precisely controlling the growth kinetics. These dielectrics demonstrate an impressive high-κ value of 10.8 and exhibit a remarkable breakdown field strength (E bd ) exceeding 10 MV cm -1 . Remarkably, the conventional molybdenum disulfide (MoS 2 ) field-effect transistor (FET) featuring a dielectric made of LaOCl showcases an almost negligible hysteresis when compared to FETs employing alternative gate dielectrics. This can be attributed to the flawlessly formed vdW interface and excellent compatibility established between LaOCl and MoS 2 . These findings will motivate the further exploration of rare-earth oxychlorides and the development of more-than-Moore nanoelectronic devices., (© 2023 Wiley-VCH GmbH.)

Schottky diode is the fundamental building blocks for modern electronics and optoelectronics. Reducing the semiconductor layer thickness could shrink the vertical size of a Schottky diode, improving its speed and integration density. Here, we demonstrate a new approach to fabricate a Schottky diode with ultrashort physical length approaching atomic limit. By mechanically laminating prefabricated metal electrodes on both-sides of two-dimensional MoS 2 , the intrinsic metal-semiconductor interfaces can be well retained. As a result, we demonstrate the thinnest Schottky diode with a length of 2.6 nm and decent rectification behavior. Furthermore, with a diode length smaller than the semiconductor depletion length, the carrier transport mechanisms are investigated and explained by thickness-dependent and temperature-dependent electrical measurements. Our study not only pushes the scaling limit of a Schottky diode but also provides a general double-sided electrodes integration approach for other ultrathin vertical devices.

The dependence of plasmon resonance on the size, shape, and interparticle spacing of single, isolated nanostructures inherently limits their light-harvesting capability to a narrow spectral band. Here, we report a facile overcurrent electrodeposition strategy to prepare fractal plasmonic black gold (B-Au) with broad-band absorption properties (over 80% throughout the range of 300-1800 nm). The broad-band absorption properties are attributed to the excitation of multiple plasmons in the B-Au, which results in strong light-matter interaction over a broad-band spectral window. Consequently, the B-Au can produce strong broad-band surface-enhanced Raman scattering (SERS) regardless of the excitation light used. These findings demonstrate that the fractal B-Au allows efficient utilization of broad spectral photons and opens up exciting opportunities for highly sensitive SERS detection, photocatalysis, and photovoltaic devices., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

Considering the importance of gene expression studies for understanding the biology of glioma stem cells (GSCs), we aimed to identify the reliable reference genes in GSCs that were derived from the glioma cell lines T98G, LN229, 090116 and 091214. Quantitative real-time reverse-transcription PCR was employed using 11 reference genes identified through a PubMed literature search, and the assessment of stability through the geNorm, Normfinder and coefficient of variation methods was performed to select suitable reference genes. We found that HPRT1 and RPL13A were the most suitable reference genes, and validated the geometric mean of these genes to normalize the expression of stemness genes by GSCs. Therefore, it is necessary to select novel cell-specific reference genes with greater expression stability for gene expression studies in GSCs.

Objective: Glioblastoma (GBM) is the most common primary malignant brain tumor regulated by numerous genes, with poor survival outcomes and unsatisfactory response to therapy. Therefore, a robust, multi-gene signature-derived model is required to predict the prognosis and treatment response in GBM., Methods: Gene expression data of GBM from TCGA and GEO datasets were used to identify differentially expressed genes (DEGs) through DESeq2 or LIMMA methods. The DEGs were then overlapped and used for survival analysis by univariate and multivariate COX regression. Based on the gene signature of multiple survival-associated DEGs, a risk score model was established, and its prognostic and predictive role was estimated through Kaplan-Meier analysis and log-rank test. Gene set enrichment analysis (GSEA) was conducted to explore high-risk score-associated pathways. Western blot was used for protein detection., Results: Four survival-associated DEGs of GBM were identified: OSMR, HOXC10, SCARA3, and SLC39A10. The four-gene signature-derived risk score was higher in GBM than in normal brain tissues. GBM patients with a high-risk score had poor survival outcomes. The high-risk group treated with temozolomide chemotherapy or radiotherapy survived for a shorter duration than the low-risk group. GSEA showed that the high-risk score was enriched with pathways such as vasculature development and cell adhesion. Western blot confirmed that the proteins of these four genes were differentially expressed in GBM cells., Conclusions: The four-gene signature-derived risk score functions well in predicting the prognosis and treatment response in GBM and will be useful for guiding therapeutic strategies for GBM patients., (Copyright 2019 Cancer Biology & Medicine.)

Doping can effectively regulate the electrical and optical properties of two-dimensional semiconductors. Here, we present high-quality Pb-doped SnSe 2 monolayer exfoliated using a micromechanical cleavage method. X-ray photoelectron spectroscopy measurement demonstrates that Pb content of the doped sample is ∼3.6% and doping induces the downward shift of the Fermi level with respect to the pure SnSe 2 . Transmission electron microscopy characterization exhibits that Pb 0.036 Sn 0.964 Se 2 nanosheets have a high-quality hexagonal symmetry structure and Pb element is uniformly distributed in the nanosheets. The current of the SnSe 2 field effect transistors (FETs) was found to be very difficult to turn off due to the high electron density. The FETs based on the Pb 0.036 Sn 0.964 Se 2 monolayer show n-type behavior with a high on/off ratio of 10 6 which is higher than any values of SnSe 2 FETs reported at the moment. The estimated carrier concentration of Pb 0.036 Sn 0.964 Se 2 is approximately six times lower than that of SnSe 2 . The results suggest that the method of reducing carrier concentration by doping to achieve high on/off ratio is effective, and Pb-doped SnSe 2 monolayer has significant potential in future nanoelectronic and optoelectronic applications.

Two-dimensional (2D) layered materials have stimulated extensive research interest for their unique thickness-dependent electronic and optical properties. However, the layer-number-dependent studies on 2D materials to date are largely limited to exfoliated flakes with relatively small lateral size and poor yield. The direct synthesis of 2D materials with a precise control of the number of atomic layers remains a substantial synthetic challenge. Here we report a systematic study of chemical vapor deposition synthesis of large-area atomically thin 2D nickel telluride (NiTe 2 ) single crystals and investigate the thickness dependent electronic properties. By controlling the growth temperature, we show that the highly uniform NiTe 2 single crystals can be synthesized with precisely tunable thickness varying from 1, 2, 3, . . . to multilayers with a standard deviation (∼0.3 nm) of less than the thickness of a monolayer layer NiTe 2 . Our studies further reveal a systematic evolution of single crystal domain size and nucleation density with the largest lateral domain size up to ∼440 μm. X-ray diffraction, transmission electron microscopy, and high resolution scanning transmission electron microscope studies demonstrate that the resulting 2D crystals are high quality single crystals and adopt hexagonal 1T phase. Electrical transport studies reveal that the 2D NiTe 2 single crystals show a strong thickness-tunable electrical properties, with an excellent conductivity up to 7.8 × 10 5 S m -1 and extraordinary breakdown current density up to 4.7 × 10 7 A/cm 2 . The systematic study and robust synthesis of NiTe 2 nanosheets defines a reliable chemical route to 2D single crystals with precisely tailored thickness and could enable the design of new device architectures based on thickness-tunable electrical properties.

This study aims to investigate the mechanisms underlying leptin-mediated crosstalk between tumor-associated macrophages (M2 macrophages) and breast cancer cells. THP1 human leukemic monocytes were induced to differentiate into M2 macrophages by PMA (100 nM) and IL-4 (20 ng/mL). Quantitative RT-PCR and Western blot revealed that leptin (100 nM) significantly increased the expression of leptin receptor (ObR) in the M2 macrophages (P < 0.01) and stimulated interleukin (IL)-8 expression in the M2 macrophages, mouse macrophage cells RAW264.7, and primary mouse peritoneal macrophages in a dose- and time-dependent manner. Leptin-induced IL-8 production was sensitive to the ERK inhibitor PD980590 (10 μmol/L), p38 MAPK inhibitor SB203580 (20 μmol/L), and anti-ObR neutralizing antibody (4 μg/mL). Leptin (100 ng/mL) substantially increased the phosphorylation of p38 and ERK1/2. Thus, leptin may induce IL-8 production in M2 macrophages by interacting with ObR to activate the p38 and ERK signaling pathways. Scratch and transwell chamber assay showed that both recombinant IL-8 and leptin-induced M2 macrophage-derived IL-8 promoted the migration and invasion of human breast cancer cells MCF7 and MDA-MB-231 (All P < 0.01). In a nude mice xenograft model of breast cancer (n = 5 per group), injection of leptin (0.1 μg/g) dramatically increased tumor volume and mass, reduced survival, exacerbated pulmonary metastasis, and elevated IL-8 and Ki67 expression in the tumor tissue (All P < 0.05) compared with PBS injection. Depletion of mouse macrophage by Clophosome®-clodronate liposome and injection of anti-mouse IL-8 neutralizing antibodies in the xenograft tumor significantly attenuated those leptin-mediated stimulations (All P < 0.05). These findings indicate that leptin may promote tumor growth and metastasis by stimulating IL-8 production in tumor-associated macrophage.

PR39, a porcine cathelicidin rich in the amino acids proline and arginine can interact with the negatively charged component of the cell surface, and rapidly penetrate cell membranes. Therefore, we hypothesized that PR39, as a membrane penetrating peptide (MPP), could be exploited as a novel carrier to deliver siRNA into the cell cytoplasm in order to knockdown target gene expression. Firstly, a complex formation of PR39 with siRNA and its cellular colocalization were investigated in our studies. Further, we optimized the ratio of the PR39/siRNA complex, cell/complex incubation period and the concentration of siRNA. The results suggest that PR39 could form a complex with siRNA, and mediate translocation of the siRNA into 4T1 cells. The optimal ratio of siRNA with PR39 was 1:90 which was found to have a maximum Stat3 gene silencing effect after 48 h treatment. Moreover, 4T1 cell proliferation, cell cycle, invasion and migration were investigated. The results suggested that Stat3 knockdown could not result in 4T1 cell proliferation inhibition and cell cycle arrest, while invasion and migration of 4T1 cells were strongly inhibited. Notably, the data also showed that in addition to inhibition of carcinogenesis, single PR39 may play a role in cell invasion and migration. PR39 and Stat3 siRNA displayed synergistic biological effects in inhibiting cell invasion and migration of 4T1 cells, which was more prominent compared with the popular Lipofectamine delivery system.