National Science Review最新文献

Low tumor-targeting delivery efficiency (Ɛ) and poor tumor penetration remain critical issues in the clinical translation of nanoparticle-based drug delivery systems. Here we report that bienzyme-powered Janus nanorobots with catalase and urease covering the same hemispheres in sequence, demonstrate chemical propulsion far exceeding translational Brownian forces and torques comparable to rotational Brownian torques by leveraging endogenous urea and H₂O₂ gradient in the tumor microenvironment, showcasing ultrasensitive chemotaxis toward biomarkers over-expressed by tumor tissues centimeters away and augmented Ɛ. After intravenous injection into a tumor-bearing mouse model, the nanorobots demonstrate significant enhancement in Ɛ, penetration depth, and cell internalization, surpassing those of passive counterparts by 209, >10, and 1970 times, respectively. When loaded with antitumor drugs, they boost tumor suppression efficacy by ∼49 times compared with passive counterparts. This work offers a new strategy for next-generation drug delivery, promising a paradigm shift for self-propelled nanorobots in precision medicine.

Twisted two-dimensional (2D) materials exhibit remarkable quantum properties due to Moiré-pattern-induced electronic band structure change, highly sensitive to nanoscale deformation from atomic-scale reconstruction. The absence of an analytical model linking deformation to twist angle limits property tunability. We developed a theoretical model characterizing deformation and energetics of twisted 2D materials. As the twist angle increases, Moiré patterns evolve from triangular partial-dislocation networks to hexagonal domains with domain walls. Using anisotropic dislocation theory, we derived analytical expressions for local rotation, strain and stress fields at small twist angles, and a non-linear formula relating energy density to twist angle, capturing the transition from rapid growth to near saturation (0°-30°). Theoretical predictions agree well with previous experimental and computational studies and our atomistic simulations for twisted bilayer graphene, hexagonal boron nitride and trilayer graphene. This work provides a theoretical foundation for twist-angle control of quantum properties, enabling design of 2D quantum devices.

Emerging evidence indicates that gut microbiota dysbiosis markedly compromises the efficacy of lung cancer immunotherapy. In our study, superparamagnetic iron oxide nanoparticle assemblies (SPIOCAs) were developed and shown to effectively inhibit lung cancer growth at a dose of 12.5 mg/kg. Pretreatment with broad-spectrum antibiotics aggravates the gut dysbiosis that blunts programmed cell death protein 1 (PD-1) blockade in tumor-bearing mice, whereas SPIOCA administration reconstituted the gut microbiota and thereby resensitized tumors to anti-PD-1 therapy. SPIOCA gavage fortified intestinal barrier integrity-evidenced by elevated ZO-1, ZO-2, Occludin and Claudin-1 expression-and potentiated antitumor immune-cell infiltration, specifically by CD8+ T cells and dendritic cells, into the tumor microenvironment. We therefore preliminarily conclude that SPIOCAs restore gut microbiota homeostasis in lung cancer, thereby enhancing intestinal barrier integrity and converting the tumor immune microenvironment from an immune desert to an immune-inflamed phenotype, ultimately improving lung cancer immunotherapy efficacy.

The transfer-free synthesis of inch-scale high-quality graphene on insulators is of paramount importance for emerging electronic and optoelectronic applications. Nevertheless, recent efforts at direct growth via the chemical-vapor-deposition route failed to produce monolayer graphene with a large wafer size (i.e. 6 inches) affording scalable uniformity and batch repeatability. Here, we report a co-field-reconciled synthetic strategy in which the synergistic optimization of thermal and gas-flow fields readily allows the uniform growth of 6-inch monolayer graphene over a sapphire wafer with batch-production capability. The temperature and flow fields are dictated via the concurrent deployment of a graphite gasket and a gas distributor plate, with the effectiveness evidenced by simulation and wafer-level characterization results. Theoretical calculations reveal that our route lowers the methane-decomposition barrier and restrains multilayer nucleation. The thus-prepared graphene exhibits impressive crystal quality, spatial uniformity and electrical performance. Six-inch wafer-scale top-gated graphene field-effect transistor arrays showcase the consistent device characteristics, with a room-temperature mobility average rivaling the state-of-the-art examples. The generality of such a route could be extended to other insulating substrates, including SiC, WC, Si₃N₄ and SiO₂. This work achieves co-field optimization during wafer-level graphene growth over insulators and lays the foundation for advancing the large-scale integration of graphene.

Isolated single-site catalysts (ISSCs) have emerged as promising materials for energy conversion and storage. However, current approaches for inorganic nanocatalysts are often ineffective in achieving precisely ordered periodic atomic arrangements of active sites, often leading to a random distribution of active-site motifs on an inorganic substrate. In this work, we introduce a novel partial-coverage-assembly strategy, leveraging graphdiyne-derived fragment ligands, to synthesize a unique Cu nanocluster catalyst with an ordered periodic arrangement of isolated single-metal Cu sites [Cu₄(TFA)₄(DPBD)₂, Cu-SMS], while maintaining identical atomicity and a homogeneous coordination microenvironment. This strategic approach significantly enhances the electron transport capability by incorporating graphdiyne-inspired bridging ligands as compared to non-coverage-assembled Cu-MMS (MMS: multiple-metal site). As a result, the Cu-SMS nanocluster catalyst exhibited superior performance in electrocatalytic nitrate reduction to ammonia, achieving a Faradaic efficiency exceeding 99%, surpassing all previously reported atomic precise metal nanocluster catalysts. Through a combination of in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy, electrochemical mass spectrometry and density functional theory calculations, we unraveled a detailed mechanistic pathway of nitrate reduction on Cu-SMS, highlighting the role of key intermediates (*NO₂, *NO, *NHO, *NHOH, *NH₂OH, *NH₂) and identifying the rate-determining step. In all, these findings present a novel methodology for synthesizing periodic SMS catalysts, emphasizing the emergent catalytic behaviors of precisely ordered metal clusters in heterogeneous catalysis.

Helical organization in soft materials is omnipresent in systems ranging from DNA and peptides to liquid crystal displays. Dynamic transformation and reconfiguration of helicity triggered non-invasively by light are highly desirable, yet challenging to control in soft-condensed matter. Herein, we report the photo-transformation of helicity in soft matter with robust manipulation of the helical pitch and inversion of chirality. The key molecular design is based on the introduction of a multi-branched dendron-like chiral photoswitch, along with balancing long-range order and short-range disorder states, featuring ultra-large helical twisting power (HTP) and initiating an extremely broad dynamic spectral range (400-3000 nm). The resonance coupling between helixes and inherent luminescence of the chiral photoswitch enables stimulated circularly polarized luminescence (CPL), with a dissymmetric factor of 1.97 approaching the theoretical limit. The precise dynamic control allows for photo-tailorable infrared beams and high dimensional coding, offering a robust approach to dynamic soft matter, chiro-optics and information processing.

Twisted homobilayer transition metal dichalcogenides-specifically twisted bilayer MoTe[Formula: see text] and twisted bilayer WSe[Formula: see text]-have recently emerged as a versatile platform for strongly correlated and topological phases of matter. These two-dimensional systems host tunable flat Chern bands in which Coulomb interactions can dominate over kinetic energy, giving rise to a variety of interaction-driven phenomena. A series of groundbreaking experiments have revealed a rich landscape of quantum phases, including integer and fractional quantum anomalous Hall states, quantum spin Hall states, anomalous Hall metals, zero-field composite Fermi liquids and unconventional superconductors, along with more conventional topologically trivial correlated states, including antiferromagnets. This review surveys recent experimental discoveries and theoretical progress in understanding these phases, with a focus on the key underlying mechanisms-band topology, electron interactions, symmetry breaking and charge fractionalization. We emphasize the unique physics of twisted transition metal dichalcogenide homobilayers in comparison to other related systems, discuss open questions and outline promising directions for future research.