Suchergebnisse

Abstract
Graphene oxide and other 2D materials such as molybdenum disulfide and boron nitride have been gaining popularity in various biochemical and industrial applications. Dendritic cells (DCs) are important innate cells that regulate adaptive immune responses and have emerged as the next immune cell of nano-science importance after the commonly published macrophages, as they can also take up nanomaterials. DCs have also been used in nanotechnology to modulate immune response in oncology and autoimmunity and it is crucial to evaluate DC compatibility of common 2D nanomaterials. By using primary human DCs, we show that all materials did not impact DC viability. In terms of cell uptake, BN was mostly located in the cytoplasm while GO was mostly found in phagosomes, and MoS2 was found in both phagosomes and cytoplasm. BN and GO increase DC maturation to different extents, while GO also leads to the release of reactive oxygen species and pro-inflammatory cytokines. BN and MoS2 increased T cell proliferation with and without the presence of DCs. BN exerts minimal toxic effect on DC viability and DC-mediated T cell polarization, although some effects were observed in T cells alone. MoS2 did not have an effect on DC maturation, unlike BN, despite having greater material association with DCs. Overall, materials ranked in term of inherent DC toxicity provided the following trend: GO > BN = MoS2, with GO most cytotoxic. With these, we hope to better shape design of 2D nanomaterials for improved immune compatibility.
* H Lin, et al. Small. 2022, 18(20), e2107652.

In this study, palm olein-based grease with a micro-molybdenum disulfide (MoS2) additive has been developed. The grease was prepared using various MoS2 concentrations to investigate the role of additives in improving grease performance. A four-ball tribological test was conducted to investigate the surface morphology, wear depth, and volume loss of the steel ball. The results indicated that the MoS2 additive reduced the coefficient of friction and wear scar diameter compared to pure palm olein grease. The value of 0.5 wt.% was considered the optimum value, reflecting the best grease performance indicated by low friction coefficient, wear diameter, wear depth, and volume loss. Elemental analysis revealed that the MoS2 additive was deposited onto the wear tracks, improving the surface protection. Thus, this additive was found to have a good potential for improving palm olein-based grease.

Various applications of transition metal dichalcogenides (TMDs) require preparation by exfoliation of precursor bulk materials. However, bulk TMDs are not always available in suitable forms and current synthesis methods may not result in appropriate crystals. This study reports synthesis of large crystals (50–100 μm) of MoS2 and ReS2, by recrystallisation of MoS2 powder or reaction of sulfate with perrhenic acid, respectively. The reactions have been performed at high pressure and temperature (≥1 GPa; ≥800 °C) in a liquid Ca-carbonate flux. The resulting crystals were characterised by electron microscopy imaging, EDS and WDS chemical analyses, and Raman spectroscopy. The carbonate matrix can be easily dissolved to recover the product TMDs. This method allows synthesis of large well-crystalline TMD compositions that are otherwise challenging to obtain. ; This research is supported by an Australian Government Research Training Program Scholarship and a Ringwood Scholarship. This work was supported by Australian Research Council grant FL130100066 to Hugh O'Neill who provided constructive comments on the manuscript.

Two-dimensional materials, including molybdenum disulfide (MoS2), present promising sensing and detecting capabilities thanks to their extreme sensitivity to changes in the environment. Their reduced thickness also facilitates the electrostatic control of the channel and opens the door to flexible electronic applications. However, these materials still exhibit integration difficulties with complementary-MOS standardized processes and methods. The device reliability is compromised by gate insulator selection and the quality of the metal/semiconductor and semiconductor/insulator interfaces. Despite some improvements regarding mobility, hysteresis and Schottky barriers having been reported thanks to metal engineering, vertically stacked heterostructures with compatible thin-layers (such as hexagonal boron nitride or device encapsulation) variability is still an important constraint to sensor performance. In this work, we fabricated and extensively characterized the reliability of as-synthesized back-gated MoS2 transistors. Under atmospheric and room-temperature conditions, these devices present a wide electrical hysteresis (up to 5 volts) in their transfer characteristics. However, their performance is highly influenced by the temperature, light and pressure conditions. The singular signature in the time response of the devices points to adsorbates and contaminants inducing mobile charges and trapping/detrapping carrier phenomena as the mechanisms responsible for time-dependent current degradation. Far from being only a reliability issue, we demonstrated a method to exploit this device response to perform light, temperature and/or pressure sensors in as-synthesized devices. Two orders of magnitude drain current level differences were demonstrated by comparing device operation under light and dark conditions while a factor up to 105 is observed at vacuum versus atmospheric pressure environments. ; European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No 895322 ; Spanish Government under Juan de la Cierva Formacion grant number FJC2018-038264-I ; Spanish Ministry of Economy, Industry and Competitivity under grant TEC2017-89800-R ; ASCENT (EU Horizon 2020 GRANT 654384) ; Science Foundation Ireland through the AMBER 2 project (12/RC/2278-P2) ; UGR-MADOC CEMIX 2D-EDEX