Visual Location of Oxygen Vacancies on Bismuth Titanate Nanosheets with Periodic Quantum Well and Promoting HO Photosynthesis.

Oxygen vacancy (OV) defect engineering plays a crucial role in enhancing photocatalytic efficiency. However, the direct visual characterization of oxygen vacancies still remains technically limited. Herein, a bismuth titanate (BiTiO, BTO-OV) model photocatalyst containing oxygen vacancies is constructed through density functional theory (DFT) calculations to reveal the influence mechanism of distinctive periodic quantum well and oxygen vacancies on the charge transfer behavior in BTO.

Hierarchically Porous Microgels with Interior Spiral Canals for High-Efficiency Delivery of Stem Cells in Wound Healing.

Chronic wound poses a serious risk to diabetic patients, primarily due to damaged skin microvasculature and prolonged inflammation at the wound site. Mesenchymal stem cell (MSC) therapy utilizing microgels as a cell delivery system has shown promise in promoting wound healing by enhancing cell viability and the secretion of bioactive factors. Retaining sufficient MSCs at injury sites is crucial for optimal therapeutic outcomes.

Infrared Spectroscopy for Diagnosing Superlattice Minibands in Twisted Bilayer Graphene near the Magic Angle.

Twisted bilayer graphene (TBG) represents a highly tunable, strongly correlated electron system. However, understanding the single-particle band structure alone has been challenging due to a lack of spectroscopic measurements over a broad energy range. Here, we probe the band structure of TBG around the magic angle using infrared spectroscopy and reveal spectral features that originate from interband transitions.

Efficient construction of high-quality sulfonated porous aromatic frameworks by optimizing the swelling state of porous structures.

Conventional post-modification methods usually face the fundamental challenge of balancing the high content of functional groups and large surface area for porous organic polymers (POPs). The reason, presumably, stems from ineffective and insufficient swelling of the porous structure of POP materials, which is detrimental to mass transfer and modification of functional groups, especially with large-sized ones. It is important to note that significant differences exist in the porous structures of POP materials in a solvent-free state after thermal activation and solvent swelling state.

Robust flat bands in twisted trilayer graphene moiré quasicrystals.

Moiré structures formed by twisting three layers of graphene with two independent twist angles present an ideal platform for studying correlated quantum phenomena, as an infinite set of angle pairs is predicted to exhibit flat bands. Moreover, the two mutually incommensurate moiré patterns among the twisted trilayer graphene (TTG) can form highly tunable moiré quasicrystals. This enables us to extend correlated physics in periodic moiré crystals to quasiperiodic systems.

Isomerization of Covalent Organic Frameworks for Efficiently Activating Molecular Oxygen and Promoting Hydrogen Peroxide Photosynthesis.

Constitutional-isomerized covalent organic frameworks (COFs), constructed by swapping monomers around imine bonds, have attracted attention for their distinct optoelectronic properties, which significantly impact photocatalytic performance. However, limited research has delved into the inherent relationship between isomerization and the enhancement of HO photosynthesis. Herein, a pair of isomeric COFs linked by imine bonds (PB-PT-COF and PT-PB-COF) is synthesized, and it is proved that isomeric COFs exhibit different rate-determining steps in the generation process of HO, resulting in a twofold increase in photocatalytic efficiency.

Nanoscale Optical Conductivity Imaging of Double-Moiré Twisted Bilayer Graphene.

A central paradigm of moiré materials relies on the formation of superlattices that yield enlarged effective crystal unit cells. While a critical consequence of this phenomenon is the celebrated flat electronic bands that foster strong interaction effects, the presence of superlattices has further implications. Here we explore the advantages of moiré superlattices in twisted bilayer graphene (TBG) aligned with hexagonal boron nitride (hBN) for passively enhancing optical conductivity in the low-energy regime.

Dispersion-Selective Band Engineering in an Artificial Kagome Superlattice.

The relentless pursuit of band structure engineering continues to be a fundamental aspect in solid-state research. Here, we meticulously construct an artificial kagome potential to generate and control multiple Dirac bands of graphene. This unique high-order potential harbors natural multiperiodic components, enabling the reconstruction of band structures through different potential contributions.

High-Mobility Compensated Semimetals, Orbital Magnetization, and Umklapp Scattering in Bilayer Graphene Moiré Superlattices.

Twist-controlled moiré superlattices (MSs) have emerged as a versatile platform for realizing artificial systems with complex electronic spectra. The combination of Bernal-stacked bilayer graphene (BLG) and hexagonal boron nitride (hBN) can give rise to an interesting MS, which has recently featured a set of unexpected behaviors, such as unconventional ferroelectricity and the electronic ratchet effect. Yet, the understanding of the electronic properties of BLG/hBN MS has, at present, remained fairly limited.

One-step biofabrication of liquid core-GelMa shell microbeads for hollow cell ball self-assembly.

There are many instances of hollow-structure morphogenesis in the development of tissues. Thus, the fabrication of hollow structures in a simple, high-throughput and homogeneous manner with proper natural biomaterial combination is valuable for developmental studies and tissue engineering, while it is a significant challenge in biofabrication field. We present a novel method for the fabrication of a hollow cell module using a coaxial co-flow capillary microfluidic device.

Atomic-level imaging of beam-sensitive COFs and MOFs by low-dose electron microscopy.

Electron microscopy, an important technique that allows for the precise determination of structural information with high spatiotemporal resolution, has become indispensable in unravelling the complex relationships between material structure and properties ranging from mesoscale morphology to atomic arrangement. However, beam-sensitive materials, particularly those comprising organic components such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), would suffer catastrophic damage from the high energy electrons, hindering the determination of atomic structures. A low-dose approach has arisen as a possible solution to this problem based on the integration of advancements in several aspects: electron optical system, detector, image processing, and specimen preservation.

Optical properties and plasmons in moiré structures.

The discoveries of numerous exciting phenomena in twisted bilayer graphene (TBG) are stimulating significant investigations on moiré structures that possess a tunable moiré potential. Optical response can provide insights into the electronic structures and transport phenomena of non-twisted and twisted moiré structures. In this article, we review both experimental and theoretical studies of optical properties such as optical conductivity, dielectric function, non-linear optical response, and plasmons in moiré structures composed of graphene, hexagonal boron nitride (hBN), and/or transition metal dichalcogenides.

Polydopamine-Modified 2D Iron (II) Immobilized MnPS Nanosheets for Multimodal Imaging-Guided Cancer Synergistic Photothermal-Chemodynamic Therapy.

Manganese phosphosulphide (MnPS ), a newly emerged and promising member of the 2D metal phosphorus trichalcogenides (MPX ) family, has aroused abundant interest due to its unique physicochemical properties and applications in energy storage and conversion. However, its potential in the field of biomedicine, particularly as a nanotherapeutic platform for cancer therapy, has remained largely unexplored. Herein, a 2D "all-in-one" theranostic nanoplatform based on MnPS is designed and applied for imaging-guided synergistic photothermal-chemodynamic therapy.

Observation of Rydberg moiré excitons.

Rydberg excitons, the solid-state counterparts of Rydberg atoms, have sparked considerable interest with regard to the harnessing of their quantum application potentials, but realizing their spatial confinement and manipulation poses a major challenge. Lately, the rise of two-dimensional moiré superlattices with highly tunable periodic potentials provides a possible pathway. Here, we experimentally demonstrate this capability through the spectroscopic evidence of Rydberg moiré excitons (X), which are moiré-trapped Rydberg excitons in monolayer semiconductor tungsten diselenide adjacent to twisted bilayer graphene.

Light Triggered Pore Size Tuning in Photoswitching Covalent Triazine Frameworks for Low Energy CO Capture.

Recently, photo switching porous materials have been widely reported for low energy costed CO capture and release via simply remoted light controlling method. However, most reported photo responsive CO adsorbents relied on metal organic framework (MOFs) functionalisation with photochromic moieties, and MOF adsorbents still suffered from chemically and thermally unstable issues. Thus, further metal free and highly stable organic photoresponsive adsorbents are necessary to be developed.

Real-Space Mapping of Local Subdegree Lattice Rotations in Low-Angle Twisted Bilayer Graphene.

In two-dimensional small-angle twisted bilayers, van der Waals (vdW) interlayer interaction introduces an atomic-scale reconstruction, which consists of a moiré-periodic network of local subdegree lattice rotations. However, real-space measurement of the subdegree lattice rotation requires extremely high spatial resolution, which is an outstanding challenge in an experiment. Here, a topmost small-period graphene moiré pattern is introduced as a magnifying lens to magnify sub-Angstrom lattice distortions in small-angle twisted bilayer graphene (TBG) by about 2 orders of magnitude.

Ultrathin Hollow Co/N/C Spheres from Hyper-Crosslinked Polymers by a New Universal Strategy with Boosted ORR Efficiency.

Porous carbon materials with hollow structure, on account of the extraordinary morphology, reveal fascinating prospects in lithium-ion batteries, electrocatalysis, etc. However, collapse in ultrathin carbon spheres due to insufficient rigidity in such thin materials obstructs further enhanced capability. Based on hyper-crosslinked polymers (HCPs) with sufficient pore structure and rigid framework, a new bottom-up strategy is proposed to construct SiO @HCPs directly from aromatic monomers.

Selective Formation of Osteogenic and Vasculogenic Tissues for Cartilage Regeneration.

Tissue-engineered periosteum substitutes (TEPSs) incorporating hierarchical architecture with osteoprogenitor and vascular niches are drawing much attention as a promising tool to support functional cells in defined zones and nourish the cortical bone. Current TEPSs usually lack technologies to closely observe cell performance, especially at the cell contact interface between distinct compartments containing defined biological configurations and functions. Here, an electrodeposition strategy is reported, which enables the selective formation of TEPSs with osteoprogenitor and vascular niches in a multiphasic scaffold in combination with different human cell types for cartilage regeneration in an in vivo osteochondral defect model.

Robotic Intracellular Electrochemical Sensing for Adherent Cells.

Nanopipette-based observation of intracellular biochemical processes is an important approach to revealing the intrinsic characteristics and heterogeneity of cells for better investigation of disease progression or early disease diagnosis. However, the manual operation needs a skilled operator and faces problems such as low throughput and poor reproducibility. This paper proposes an automated nanopipette-based microoperation system for cell detection, three-dimensional nonovershoot positioning of the nanopipette tip in proximity to the cell of interest, cell approaching and proximity detection between nanopipette tip and cell surface, and cell penetration and detection of the intracellular reactive oxygen species (ROS).

Realizing One-Dimensional Electronic States in Graphene via Coupled Zeroth Pseudo-Landau Levels.

Strain-induced pseudomagnetic fields can mimic real magnetic fields to generate a zero-magnetic-field analog of the Landau levels (LLs), i.e., the pseudo-Landau levels (PLLs), in graphene.

Heterogeneous spheroids with tunable interior morphologies by droplet-based microfluidics.

Heterogeneous spheroids that mimic the complex three-dimensional environment of natural tissues are needed in various biomedical applications. Geometric cues from cellular matrix play invaluable roles in governing cell behavior and phenotype. However, the structural complexity of interior morphologies of spheroids is currently limited due to poor spatial resolution of positioning/orientation of cellular constructs.

Grafting Hypercrosslinked Polymers on TiO Surface for Anchoring Ultrafine Pd Nanoparticles: Dramatically Enhanced Efficiency and Selectivity toward Photocatalytic Reduction of CO to CH.

Metal deposition with photocatalyst is a promising way to surmount the restriction of fast e /h recombination to improve the photocatalytic performance. However, the improvement remains limited by the existing strategies adopted for depositing metal particles due to the serious aggregation and large unconnected area on photocatalyst surface. Here, a strategy is proposed by directly grafting hypercrosslinked polymers (HCPs) on TiO surface to construct Pd-HCPs-TiO composite with uniform dispersion of ultrafine Pd nanoparticles on HCPs surface.