Nanoscale Advances最新文献

Carbon nanotubes (CNTs) are useful nanomaterials owing to their distinct functions that depend on their structure and diameter; therefore, CNTs have recently attracted much attention. Catalytic chemical vapor deposition using metal nanoparticles as catalysts is one of the most useful methods for synthesizing CNTs. However, fine control of the CNT diameter has been technically difficult at the 1 nanometer level owing to the size distribution of metal nanoparticles and the difficulty in suppressing their aggregation during the CNT growth reaction. In this study, we developed a method for simultaneously conducting nanoparticle formation and CNT growth through the in situ preparation of nanoparticles using highly dispersed metal clusters on a support substrate as seeds. In this method, the migration and aggregation behavior of seed metal clusters on a substrate upon heating uniformly induces nanoparticle formation until nanoparticles are enlarged to suitable size for CNT growth, and then CNTs grow with a diameter corresponding to that of the nanoparticles. The nanoparticle size does not change afterward by spatial separation of the nanoparticles from the substrate due to the tip-growth mechanism of CNTs. Detailed analysis focusing on cobalt as a catalyst demonstrated that the diameters of the multi-walled CNTs could be simply tuned solely by modifying the reaction temperature and time. This result reveals that the synthetic concept using the seed clusters enables the control of the CNT size to a certain extent using only temperature control (thermal energy), without conventional separation processes for synthesizing nanoparticles and determining conditions to retain nanoparticle size.

TiO₂ nanotube flow-through membranes (TNTsM) were fabricated via anodization of Ti foil and explored as a biosensing platform for creatinine detection. The electrodes were prepared in different configurations including TNT membrane with top surface up (TNTsMTU/TNPs/FTO), TNT membrane with bottom surface up (TNTsMBU/TNPs/FTO), TNT membrane with top surface up containing nanograss (TNTsMNG/TNPs/FTO), and TNTs/NPs/FTO and TiO₂ nanoparticles (TNPs) film on fluorine doped tin oxide (TNPs/FTO). Electrochemical studies depict the higher electrochemical activity (sensitivity ∼19.88 μA μM⁻¹ cm⁻²) of TNTsMTU/TNPs/FTO towards creatinine compared to other configurations. This exceptional performance of the TNTsMTU/TNPs/FTO electrode results from the flow-through nature of TNTsM and the removal of the bottom oxide barrier layer through etching in H₂O₂. The underlying layer of TiO₂ NPs also contributes to the higher current response of the TNTsMTU/TNPs/FTO. The relevance of the biosensor structural design is demonstrated by the increased amperometric response of TNTsMTU/TNPs/FTO and greater redox peak current in cyclic voltammograms. Furthermore, the higher selectivity, stability, and reproducibility of the electrode can be due to the suitable redox potential, chemical stability, and controlled fabrication process of TNT membranes.

Retraction of ‘Unique and outstanding catalytic behavior of a novel MOF@COF composite as an emerging and powerful catalyst in the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives’ by Mohammad Ali Ghasemzadeh et al., Nanoscale Adv., 2023, 5, 7031–7041, https://10.1039/D3NA00805C.

We report a synthetic strategy to produce nano-immobilised and organosilica-shielded enzymes of which the biocatalytic activity is, by design, chemically enhanced under reductive conditions. The enzymes were immobilised onto silica nanoparticles through a reduction-responsive crosslinker and further shielded in an organosilica layer of controlled thickness. Under reducing conditions, disulphide bonds linking the protein to the carrier material were reduced, triggering enzyme activation. The organosilica shield prevents the enzymes from leaching from the nanobiocatalysts and preserves their integrity.

Liver cancer, with its robust metastatic propensity, imposes a substantial global health burden of around 800 000 new cases annually. Mutations in the Wnt/β-catenin pathway genes are common in liver cancer, driving over 80% of cases. Targeting this pathway could potentially lead to better treatments. The aim of the present study was to develop a novel strategy for targeting the Wnt/β-catenin pathway while blocking the growth and division, of liver cancer cells and downregulating gene expression. This was achieved by formulating a repurposed drug (mefloquine)-loaded garlic nano-emulsion (GNE) with gold nanoparticles (GNPs) as a core–shell nano-emulsion (MQ/GNE-GNP). The biocompatible core–shell nano-emulsion (MQ/GNE-GNP) exhibited a size distribution in the range of 50–100 nm, high stability, excellent hydrophilicity, good biosafety, and sustained release. Human liver cancer cells were exposed to MQ/GNE, GNPs, and MQ/GNE-GNP at varying concentrations, and the effects were assessed through analysis of the cytotoxicity, reactive oxygen species, cell death, cell cycle analysis, and gene expression studies. It was found that MQ/GNE-GNP arrested HepG2 cells in the sub G0/G1phase and induced apoptosis. The anticancer efficacy of the core–shell nano-emulsion (MQ/GNE-GNP) resulted in higher cell death in the AO/PI staining studies, demonstrating its greater anticancer efficacy. The administration of MQ/GNE-GNP downregulated the overall expression of nuclear β-catenin, thereby suppressing the Wnt/β-catenin pathway. The protein expression level of Wnt 1 was upregulated, while β-catenin expression was significantly decreased. The core–shell nano-emulsion, incorporating a repurposed drug, could disrupt the β-catenin connections in the Wnt/β-catenin pathway. In conclusion, MQ/GNE-GNP could be a promising core–shell nano emulsion for the effective treatment of liver cancer by targeting the Wnt/β-catenin pathway.

Self-assembly of small molecules into supramolecular architectures is a sustainable alternative to new advanced material design. Herein, the design and synthesis of a self-assembling system containing four covalently linked hybrid guanine and cytosine (G∧C) units that were connected through bifunctional amines are reported. These tetra G∧C motifs were characterized and self-assembled in water and methanol to produce discrete nanostructures. Each module has 24 sites for intermolecular hydrogen bonding and it is proposed that in solution the four G∧C units per molecule align into a linear stack which in turn self-assembles into a hexameric super-helix held together by 72 intermolecular hydrogen bonds. Stacking of these nano-helices led to the formation of quad rosette nanotubes.

The mechanical, thermal and dynamical stabilities, electronic structure, contact type, and height of the barrier at the interface of TaX₂ (X = S, Se, Te) and BY (Y = P, As, Sb) metal–semiconductor (MS) contact are investigated via first principles calculations. Binding energies, mechanical properties, phonon spectra and ab initio molecular dynamics (AIMD) simulations confirm the stabilities of these systems. TaX₂–BY (X = S, Se, Te; Y = P, As, Sb) MS van der Waals heterostructures (vdWHs) are found to be metal with a Schottky contact at the interface. Formation of the n-type Schottky contact at the interface of TaX₂–BY (X = S, Se, Te; Y = P, As, Sb) MS vdWHs favors electron conduction over hole conduction. Small (higher) effective mass (carrier mobility) make TaS₂–BSb, TaSe₂–BSb and TaTe₂–BSb MS vdWHs, potential candidates for high speed nanoelectronic applications. Bader charge analysis shows that at the interface of TaX₂–BY (X = S, Se, Te; Y = P, As, Sb) MS vdWHs, in TaX₂ (BP, BAs) the electrons transfer from the TaX₂ layer to the BP and BAs layer, while in TaX₂ (BSb) the electrons transfer from the BSb layer to TaX₂ layer.

Photo-/electrocatalysis serves as a cornerstone in addressing global energy shortages and environmental pollution, where the development of efficient and stable catalysts is essential yet challenging. Despite extensive efforts, it's still a formidable task to develop catalysts with excellent catalytic behaviours, stability, and low cost. Because of its high precision, favorable controllability and repeatability, radiation technology has emerged as a potent and versatile strategy for the synthesis and modification of nanomaterials. Through meticulous control of irradiation parameters, including energy, fluence and ion species, various inorganic photo-/electrocatalysts can be effectively synthesized with tailored properties. It also enables the efficient adjustment of physicochemical characteristics, such as heteroatom-doping, defect generation, heterostructure construction, micro/nanostructure control, and so on, all of which are beneficial for lowering reaction energy barriers and enhancing energy conversion efficiency. This review comprehensively outlines the principles governing radiation effects on inorganic catalysts, followed by an in-depth discussion of recent advancements in irradiation-enhanced catalysts for various photo-/electrocatalytic applications, such as hydrogen and oxygen evolution reactions, oxygen reduction reactions, and photocatalytic applications. Furthermore, the challenges associated with ionizing and non-ionizing radiation are discussed and potential avenues for future development are outlined. By summarizing and articulating these innovative strategies, we aim to inspire further development of sustainable energy and environmental solutions to drive a greener future.

Carbon dots have recently attracted tremendous scientific attention thanks to their enhanced luminescence properties, photostability and low toxicity. In particular, red-emitting carbon dots (RCDs) are assuming increasing importance in biomedical applications, such as bio-imaging and phototherapy. At the same time, the possibility to create functional and complex objects by means of vat-photopolymerization-based three-dimensional (3D) printing techniques is continuously growing. This work describes the synthesis of long-chain surface-modified red emitting carbon dots, L-RCDs by esterification of RCDs, obtained from green reagents with a new solvothermal synthesis, and their employment as fluorescent additives in two formulations of photopolymerizable resins. The printing process proceeded smoothly in all cases, and red-emitting objects with different mechanical properties have been successfully obtained.

MicroRNAs (miRNAs) play crucial roles in the regulation of immune cell differentiation and the immune response during allergic rhinitis (AR). Studies have shown that miRNA-155 is significantly upregulated in AR pathogenesis. Therefore, miRNA-155 can be used as a biomarker for AR diagnosis. Although fluorescent biosensors based on upconversion nanoparticles (UCNPs) have made significant advances in the detection of miRNAs, developing UCNPs with polymer coatings, efficient surface passivation, and DNA functionalization for hybrid sensing in biological media remains challenging. Herein, hairpin DNA1 (H1) is modified into a thin polysulfonic acid layer on UCNPs by sulfonamide bonds, and the fluorescence of the UCNPs is quenched by the fluorescence resonance energy transfer (FRET) process of BHQ3 carried by H1. When the target miRNA-155 is present, the hairpin structure of H1 is opened, allowing BHQ3 to move away from the UCNP surface, and the fluorescence of UCNP is restored. At the same time, hairpin DNA1 (H2) can combine with H1 to replace the miRNA-155 that is bound to H1 with the help of the opening stem ring structure of H1, and the replaced miRNA-155 can continue to react with H1 to amplify the fluorescence signal. Under the optimal experimental conditions, the linear range of miRNA-155 is 0.01–3 nM, with a detection limit of 1.14 pM. Furthermore, the constructed biosensor has been applied to determine miRNA-155 in serum samples, and the spiked recoveries range from 99.8% to 104.8%, which indicates that the developed assay has potential applications in monitoring allergic rhinitis or other miRNA related diseases.