groups (OH, O, F), n usually ranges from 1 to 3, and x reflects the number of terminal groups. [1-5] MXenes have drawn much attention for their potential use in energy storage, [1,6] sensing technology, [7,8] functional coatings, [9-11] plasmonics, [12] and catalytic applications [13-15] due to their high electrical conductivity, hydrophilicity, and surface charge. Most of those properties can be traced back to their metallic-like 2D structure and functional groups attached during the etching and delamination processes. [4,5,16-18] However, recent studies suggest that MXenes are prone to react with dissolved oxygen and water molecules, which results in the formation of transition metal oxides and carbon residues. [3,19,20] Initially, Zhang et al. claimed that MXene oxidizes due to the contact with dissolved oxygen in water. [20] However, Huang et al. and our group also demonstrated that water molecules, rather than oxygen molecules, play a critical role in MXene degradation. [21,22] MXenes were reported to oxidize and degrade more rapidly in water rather than in organic solvents, air, or polymer matrixes. [3,23] Zhang et al., Chae et al., and Habib et al. (our group) also found that temperature and humidity have an influence on MXene oxidation. [3,19,20] They proposed that low temperatures and low humidity can mitigate the oxidation of MXene nanosheets due to the slower reaction kinetics and reduced exposure to water molecules, respectively. In addition, MXene nanosheets that are single-to few-layered or have smaller lateral size oxidize faster than multilayered MXene clay particles or larger-size nanosheets. MXenes oxidize rapidly when exposed to oxidizers such as hydrogen peroxide or treated by flash-annealing at high temperatures. [24,25] In addition, elemental composition may influence the oxidation kinetics. [26] VahidMohammadi et al. and Huang et al. reported that M 2 XT x MXenes, such as V 2 CT x and Ti 2 CT x , oxidize and degrade much faster than the more common M 3 X 2 T x , such as Ti 3 C 2 T x. [21,27] Other aspects may also contribute to the oxidation of MXenes, such as the amount and types of terminal groups, etching conditions, ultraviolet exposure, and the number of defects on the MXene nanosheets.

Tumour vasculature is generally disordered because of the production of excessive angiogenic factors by tumour cells, which results in tumour progression and reduces the effectiveness of radiotherapy or chemotherapy. Transient anti-angiogenic therapies that regulate tumour vascular morphology and function and improve the efficiency of antitumour therapy are under investigation. Recombinant human endostatin (Endostar/rhES) is a vascular angiogenesis–disrupting agent that has been used to treat non-small cell lung cancer (NSCLC) in the clinical setting. In this study, we used gold nanoparticles (AuNPs) as a drug-delivery system (DDS) for targeted tumour delivery of rhES for short therapy, which resulted in transient tumour vascular normalization, reduced permeability and hypoxia, strengthened blood vessel integrity, and increased blood-flow perfusion. Moreover, combination therapy with 5-FU over this timeframe was substantially more effective than 5-FU monotherapy. In conclusion, our research demonstrates the potential use of AuNPs as a drug-delivery platform for transporting rhES into a tumour to induce transient tumour vascular normalization and enhance the antitumour efficacy of cytotoxic drugs.

Bacterial pathogens are responsible for millions of cases of illnesses and deaths each year throughout the world. The development of novel surfaces and coatings that effectively inhibit and prevent bacterial attachment, proliferation, and growth is one of the crucial steps for tackling this global challenge. Herein, we report a dual-functional coating for aluminum surfaces that relies on the controlled immobilization of lysozyme enzyme (muramidase) into interstitial spaces of presintered, nanostructured thin film based on ∼200 nm silica nanoparticles and the sequential chemisorption of an organofluorosilane to the available interfacial areas. The mean diameter of the resultant lysozyme microdomains was 3.1 ± 2.5 μm with an average spacing of 8.01 ± 6.8 μm, leading to a surface coverage of 15.32%. The coating had an overall root-mean-square (rms) roughness of 539 ± 137 nm and roughness factor of 1.50 ± 0.1, and demonstrated static, advancing, and receding water contact angles of 159.0 ± 1.0°, 155.4 ± 0.6°, and 154.4 ± 0.6°, respectively. Compared to the planar aluminum, the coated surfaces produced a 6.5 ± 0.1 (>99.99997%) and 4.0 ± 0.1 (>99.99%) log-cycle reductions in bacterial surfaces colonization against Gram-negative Salmonella Typhimurium LT2 and Gram-positive Listeria innocua, respectively. We anticipate that the implementation of such a coating strategy on healthcare environments and surfaces and food-contact surfaces can significantly reduce or eliminate potential risks associated with various contamination and cross-contamination scenarios.

Angiogenesis is a process by which vessels are formed through preexisting ones, and this plays a key role in the progression of solid tumors. However, tumor vessels are influenced by excessive pro-angiogenic factors, resulting in deformed structures that facilitate the intravasation of tumor cells into the circulation and subsequent metastasis. Moreover, abnormal tumor vessels have low blood perfusion and thereby decreased oxygen infusion into tumors. This results in a hostile microenvironment that promotes epithelial–mesenchymal transition (EMT), a process in which epithelial cells lose their polarity and gain increased motility, which is associated with metastasis and invasion. Here, we demonstrate that gold nanoparticles (AuNPs) facilitate tumor vasculature normalization, increase blood perfusion and alleviate hypoxia in melanoma tumors. Additionally, AuNPs were observed to reverse EMT in tumors, accompanied by the alleviation of lung metastasis. These AuNPs inhibited the migration of B16F10 cells and reversed EMT in B16F10 cells, indicating that AuNPs could directly regulate EMT independent of improvements in hypoxia. Taken together, our data demonstrated that AuNPs could induce tumor vasculature normalization and reverse EMT, resulting in decreased melanoma tumor metastasis.

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Violet phosphorus is another promising layered semiconducting elemental structure for electronic and optoelectronic applications. Violet phosphorus quantum dots (VPQDs) have unique optical and electronic properties due to quantum mechanics. However,...

IV-VI monochalcogenide SnSe or SnS has recently been proposed as a promising two-dimensional (2D) material for valleytronics and thermoelectrics. We report the synthesis of SnSe nanoflakes and nanostructured thin films with chemical vapor deposition method and their thermoelectric properties. As grown SnSe nanostructures are found to be intrinsically p-type and the single SnSe nanoflake field effect transistor was fabricated. By Ag doping, the power factor of SnSe nanostructured thin films can be improved by up to one order of magnitude compared to the “intrinsic” as grown materials. Our work provides an initial step in the pursuit of IV-VI monochalcogenides as novel 2D semiconductors for electronics and thermoelectrics.

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