Nano Research最新文献

The use of bioinert materials is crucially important for medicine and bioengineering. The most popular systems in this context are oligo- and poly(ethylene glycols) (OEGs and PEGs), applied generally in different forms as bulk materials, thin films, and functional molecular groups. Here, I review the fabrication, properties, and applications of porous hydrogel PEG films (PHFs) and nanosheets (PHNs) formed by thermally activated crosslinking of amino- and epoxy-terminated, star-branched PEG oligomers with variable molecular weight. These systems possess various useful characteristics, including tunable thickness and porosity, hydrogel properties, bioinertness, robustness, and extreme elasticity. They can serve as the basis for composite materials, advanced nanofabrication, and lithography, bioinert supports for high-resolution transmission electron microscopy, susceptible elements in micro-electromechanical systems, and basic building blocks of temperature, humidity, chemical, and biological sensors. Representative examples of the respective applications are provided. Even though these examples span a broad field-from nanoengineering to biosensing, the applications of the PHFs and PHNs are certainly not limited to these cases but can be specifically adapted and extended to other fields, such as tissue engineering and drug delivery, relying on versatility and tunability of these systems.

The impact of the size effect on the color and photoluminescence (PL) of quantum dots (QDs) has sparked a revolutionary field of research, culminating in the prestigious Nobel Prize in 2023. Prior to their widespread popularization and large-scale commercialization, it is of paramount importance to effectively manipulate and optimize their optical properties. In this review, we place specific emphasis on the striking correlation between the optical characteristics of QDs and their size, structure, composition, and interface environment. We commence by tracing the evolution of quantum dot technology and subsequently categorizing QDs while outlining their typical synthesis methods. This is followed by a deep dive into the pivotal roles of size, composition, structure, and interfacial ligands in fine-tuning, optimizing, and enhancing the optical properties of QDs. Additionally, we illustrate the luminescence enhancement and charge transfer phenomena stemming from the heterojunction between semiconductor QDs and metal nanomaterials, which contribute to improved performance. Lastly, we introduce the burgeoning field of chiral QDs and their innovative applications. Armed with this knowledge, QDs can be readily tailored to exhibit adjustable luminous characteristics across the entire spectrum, boasting high luminous efficiency through multifaceted regulation. These advancements render QDs even more enticing and promising for a wide array of applications.

Ammonia plays a vital role in present agriculture and industry, and is also regarded as a next-generation clean energy carrier. The development of electrocatalysis raises an opportunity to make ammonia synthesis compatible with intermittent and variable renewable energy sources such as solar and wind energy. However, the direct ammonia electrosynthesis from N₂ reduction is still challenging due to the much easier hydrogen evolution competition reaction. In this perspective, we propose a novel strategy for ammonia electrosynthesis from air and water based on the coupling of anodic nitrogen oxidation and cathodic nitrate reduction. Possible methods for breaking the bottlenecks of anodic nitrogen oxidation and cathodic nitrate reduction are discussed separately. After that, key issues that need to be considered in the coupled system are proposed for the application of this strategy.

Lipid nanoparticles (LNPs) have delivered RNA to hepatocytes in patients after intravenous administration. These clinical data support efforts to design LNPs that transfect cells in the central nervous system (CNS). However, delivery to the CNS has been difficult, in large part because quantifying on-target delivery alongside common off-target cell types in adult mice remains challenging. Here we report methods to isolate different cell types from the CNS, and subsequently present mRNA delivery readouts using a liver-detargeted LNP. These data suggest that LNPs without targeting ligands can transfect cerebral endothelial cells in mice after intravenous administration. Given the difficulty of crossing the blood–brain barrier, they also underscore the value of quantifying delivery in the CNS with cell-type resolution instead of whole-tissue resolution.

Chiral inorganic materials have attracted great attention owning to their unique physical and chemical properties attributed to the symmetry-breaking of their nanostructures. Chiral inorganic materials can be endowed with chiral geometric configurations from achiral space group crystals through lattice twisting, screw dislocations or hierarchical self-assembled spiral morphologies, showing various characteristic chiral anisotropy. However, the multilevel chirality in chiral nickel molybdate films (CNMFs) remains to be elaborately excavated. In this paper, we report three hierarchical levels of chirality in CNMFs, spanning from the atomic to the micron scale, including primary helically coiled nanoflakes with twisted atomic crystal lattices, secondary helical stacking of layered nanoflakes, and tertiary asymmetric morphology between adjacent nanoparticles. Our findings may enrich the chiral self-assembly structural types and provide valuable insights for the comprehensive analysis path of hierarchical chiral crystals.

Dimensional regulation in polyoxometalates is an effective strategy during the design and synthesis of polyoxometalates-based high proton conductors, but it is not available to date. Herein, the precise regulation of dimensionality has been realized in an unprecedented gigantic molybdenum blue wheel family featuring pentagonal {(W)Mo₅} motifs through optimizing the molar ratio of Mo/W, including [Gd₂Mo₁₂₄W₁₄O₄₂₂(H₂O)₆₂]³⁸⁻ (0D-{Mo₁₂₄W₁₄}, 1), [Mo₁₂₆W₁₄O₄₄₁(H₂O)₅₁]⁷⁰⁻ (1D-{Mo₁₂₆W₁₄}_n, 2), and [Mo₁₂₄W₁₄O₄₃₀(H₂O)₅₀]⁶⁰⁻ (2D-{Mo₁₂₄W₁₄}_n, 3). Such important {(W)Mo₅} structural motif brings new reactivity into gigantic Mo blue wheels. There are different numbers and sites of {Mo₂} defects in each wheel-shaped monomer in 1–3, which leads to the monomers of 2 and 3 to form 1D and 2D architectures via Mo–O–Mo covalent bonds driven by {Mo₂}-mediated H₂O ligands substitution process, respectively, thus achieving the controllable dimensional regulation. As expected, the proton conductivity of 3 is 10 times higher than that of 1 and 1.7 times higher than that of 2. The continuous proton hopping sites in 2D network are responsible for the enhanced proton conductivity with lower activation energy. This study highlights that this dimensional regulation approach remains great potential in preparing polyoxometalates-based high proton conductive materials.

Crystallinity and crystal structure greatly influence the photocatalytic behavior of photocatalysts. Pristine g-C₃N₄ produced by traditional thermal-induced polycondensation reaction bears low crystallinity and thus poor photoactivity, which originates from the incomplete polymerization of the precursor containing amine groups, abundant hydrogen bonds, and unreacted amino, as well as cyanide functional groups in the skeleton. During photocatalytic process, these residual functional groups often work as electron trap sites, which may hinder the transfer of electrons on the plane, resulting in low photoactivity. Fortunately, crystalline carbon nitride (CCN) was reported as a promising photocatalyst because its increased crystallinity not only reduces the number of carriers recombination centers, but also increases charge conductivity and improves light utilization due to extended π-conjugated systems and delocalized π-electrons. As such, we summarize the recent studies on CCN-based photocatalysts for the photoactivity enhancement. Firstly, the unique structure and properties of CCN materials are presented. Next, the preparation methods and modification strategies are well outlined. We also sum up the applications of CCN-based materials in the environmental purification and energy fields. Finally, this review concerning CNN materials ends with prospects and challenges in the obtainment of high crystallinity by effective techniques, and the deep understanding of photocatalytic mechanism.

Over the last two decades, small activating RNAs (saRNAs) have quickly moved from discovery to clinical trials. Characterized as 20 nucleotide long, double stranded RNA, saRNAs have the unique ability to increase gene transcription at the chromatin level. This therapeutic modality has great potential as a safe and redosable alternative to gene therapy by increasing target protein expression without changing the genetic sequence. We describe the successful in vivo saRNA delivery vectors and found that similar to small interfering RNA (siRNA) and mRNA targeting tissues outside the liver works best at the end of a needle. We highlight nanoparticle vectors and RNA-conjugates, where some success has been reported for non-hepatic delivery of saRNA-aptamers.

Powered by clean energy, the hydrogen fuel production from seawater electrolysis is a sustainable green hydrogen technology, however, chlorine corrosion and correlative oxidation reactions severely erode the catalysts. Our previous work demonstrates that direct seawater electrolysis without a desalination process and strong alkali addition can be realized by introducing a hard Lewis acid oxide on the catalyst surface to capture OH⁻. However, the criteria for selecting Lewis acid oxides and the origin of OH⁻ enrichment in chlorine chemistry inhibition on the catalyst surface remain unexplored. Here, we compare the ability of a series of Lewis acid oxides with different acidity constants (pKa), including MnO₂, Fe₂O₃, and Cr₂O₃, to enrich OH⁻ on the Co₃O₄ anode catalyst surface. Comprehensive analyses suggest that the lower pKa value of the Lewis acid oxide, the higher concentration of OH⁻ enriched on Co₃O₄ surface, and the lower Cl⁻ concentration. As established correlation among pKa of Lewis acid oxide, OH⁻ enrichment and Cl⁻ repulsion provide direct guidance for future design of highly active, selective and durable catalysts for natural seawater electrolysis.

Resistance to gemcitabine in pancreatic cancer poses a significant clinical challenge. Further investigation is warranted to assess whether nano-formulation strategy can be employed to enhance the sensitivity of resistant strains to gemcitabine therapy. In this study, using gemcitabine-resistant pancreatic cancer cell lines, we examined the therapeutic potential of a gemcitabine nanodelivery platform and assessed the ability to overcome drug resistance against resistant strains. Silencing of human equilibrative nucleoside transporter 1 (hENT1) led to reduced cellular uptake of gemcitabine, resulting in chemoresistance in pancreatic cancer. Gemcitabine nanoparticles circumvented the entry blockade caused by hENT1 silencing through endocytosis. Nanoparticle entry via clathrin-mediated endocytosis increased intracellular gemcitabine accumulation in gemcitabine-resistant pancreatic cancer cells. Moreover, gemcitabine nanoparticles are preferential in vivo delivery to tumor tissues, likely due to the enhanced permeability and retention effect. In comparison to free gemcitabine, gemcitabine nanoparticles demonstrate a more pronounced cytotoxic effect on gemcitabine-resistant pancreatic cancer cells, with favorable biosafety. This study improved the efficacy of gemcitabine through nanotechnology, providing a novel strategy to address gemcitabine-resistant pancreatic cancer.