Communications Materials最新文献

The blood-brain barrier, essential for protecting the central nervous system, also restricts drug delivery to this region. Thus, delivering drugs across the blood-brain barrier is an active research area in immunology, oncology, and neurology; moreover, novel methods are urgently needed to expand therapeutic options for central nervous system pathologies. While previous strategies have focused on small molecules that modulate blood-brain barrier permeability or penetrate the barrier, there is an increased focus on biomedical devices-external or implanted-for improving drug delivery. Here, we review device-assisted drug delivery across the blood-brain barrier, emphasizing its application in glioblastoma, an aggressively malignant primary brain cancer in which the blood-brain barrier plays a central role. We examine the blood-brain barrier and its features in glioblastoma, emerging models for studying the blood-brain barrier, and device-assisted methods for crossing the blood-brain barrier. We conclude by presenting methods to monitor the blood-brain barrier and paradigms for combined cross-BBB drug delivery.

Recent insights into the function and composition of cell membranes have transformed our understanding from primarily viewing these structures as passive barriers to recognizing them as dynamic entities actively involved in many cellular functions. This review highlights advances in the photopharmacology of phospholipids, emphasizing in particular the role of diacylglycerophospholipids and the impact of their polymorphic nature on synthetic and cellular membrane properties and metabolic processes. We explore photoswitchable diacylglycerophospholipids, termed 'photolipids', which permit precise, reversible modifications of membrane properties via light-induced isomerization. The ability to optically switch phospholipid properties has potential applications in controlling membrane dynamics, protein function, and cellular signaling pathways, and offers promising strategies for drug delivery and treatment of diseases. Developments in azobenzene and hemithioindigo based photolipids are discussed, underscoring their utility in biomedical and biomaterial science applications due to their unique photophysical properties.

The incommensurate spin density wave (SDW) of Chromium represents the classic example of itinerant antiferromagnetism induced by the nesting of the Fermi surface, which is further enriched by the co-presence of a charge density wave (CDW). Here, we explore its electronic band structure using soft-X-ray angle-resolved photoemission spectroscopy (ARPES) for a proper bulk-sensitive investigation. We find that the long-range magnetic order gives rise to a very rich ARPES signal, which can only be interpreted with a proper first-principles description of the SDW and CDW, combined with a band unfolding procedure, reaching a remarkable agreement with experiments. Additional features of the SDW order are obscured by superimposed effects related to the photoemission process, which, unexpectedly, are not predicted by the free-electron model for the final states. We demonstrate that, even for excitation photon energies up to 1 keV, a multiple scattering description of the photoemission final states is required.

The H₂Se molecule and the van der Waals compound (H₂Se)₂H₂ are both unstable upon room temperature compression, dissociating into their constituent elements above 22 GPa. Through a series of high pressure-high temperature diamond anvil cell experiments, we report the unexpected formation of a novel compound, SeH₂(H₂)₂ at pressures above 94 GPa. X-ray diffraction reveals the metallic sublattice to adopt a tetragonal (I4₁/a m d) structure with density functional theory calculations finding a small distortion due to the orientation of H₂ molecules. The structure comprises of a network of zig-zag H-Se chains with quasi-molecular H₂ molecular units hosted in the prismatic Se interstices. Electrical resistance measurements demonstrate that SeH₂(H₂)₂ is non-metallic up to pressures of 148 GPa. Investigations into the Te-H system up to pressures of 165 GPa and 2000 K yielded no compound formation. The combined results suggest that the high pressure phase behavior of each chalcogen hydride is unique and more complex than previously thought.

Co₃Sn₂S₂ has been reported to be a Weyl semimetal with c-axis ferromagnetism below a Curie temperature of 177 K. Despite the large interest in Co₃Sn₂S₂, the magnetic structure is still unclear. Recent studies have challenged the magnetic phase diagram of Co₃Sn₂S₂ by reporting unusual magnetic phases including the presence of exchange bias. Here we show, using X-ray Magnetic Circular Dichroism, a shift in the magnetization hysteresis loop, reminiscent of exchange bias and establish that the magnetic moment in Co arises from the spin, with negligible orbital moment. At 6 K, using spatially-resolved angle-resolved photoemission spectroscopy, we detect a butterfly-shaped electronic band structure at small regions of the sample distinct from the known ferromagnetic band structure. Our density functional theory calculations suggest that the butterfly bands correspond to an antiferromagnetic phase. Separately, we detect a sharp flat band at the Fermi level at some regions in the sample, which we attribute to a surface state. These different electronic states found in a stoichiometric intermetallic invite further efforts to explore the origin and nature of the electronic inhomogeneity associated to magnetism on the mesoscale.

Magnetic domain formation in two-dimensional materials offers insight into the fundamentals of magnetism and serves as a catalyst for the advancement of spintronics. In order to propel these developments, it is crucial to acquire an understanding of the evolution of magnetic ordering at the nanometer scale. In particular, two-dimensional magnetic insulators allow for the realization of atomically sharp magnetoresistive tunneling junctions with nonmagnetic electrodes, therefore lifting one of the major constraints for the realization of computing in memory based on magnetoresistive elements. In this study, we visualize magnetic ordering in monolayers of annite, a fully air-stable layered magnetic mica. Using a nanometer-scale scanning superconducting quantum interference device microscopy, we directly observe domain formation in this representative of two-dimensional magnetic phyllosilicates.

Biointerfacing techniques for connecting implants to living tissues are advancing, but matching stiffness at hard-soft interfaces, such as between tendon and bone, remains challenging. This is critical for improving biomechanical tissue models, repairing trauma, and integrating soft robotic technologies like artificial muscles. Here we introduce a 3D-printable, biocompatible composite combining a hydrogel (gelatin methacryloyl) with a hybrid resin of diacrylates and epoxide. By adjusting the mixture ratio, the material's elastic modulus spans a wide physiological range, from 15 kPa (soft brain tissue) to 1.4 GPa (similar to bone), covering six orders of magnitude. Mechanical tests confirm this tunability, and cytocompatibility tests show high cell viability, proliferation, and metabolic activity. The approach offers a path to creating efficient gradient stiffness interfaces, potentially leading to more accurate tissue phantoms and devices for human body repair and augmentation, especially where continuous hard-to-soft transitions are essential.

Growing environmental concerns are driving demand for energy-saving strategies. Thermochromic smart windows offer a practical solution by passively regulating sunlight in homes and offices. Despite recent progress, current technologies still face challenges in achieving the thermal durability and mechanical robustness necessary for long-term use, combined with a rapid transition below 30 °C. Here we report a thermochromic hydrogel assembled from poly(N,N-dimethylaminoethyl methacrylate) and 2,2,2-trifluoroethyl methacrylate that produces flexible films on a large scale. This hydrogel rapidly ( ~ 3 s) and reversibly becomes turbid above a tunable transition temperature spanning the human comfort zone, and maintains its thermochromic property even when mechanically stretched with 500% strain. The film's high modulation of solar transmittance (70.6%) and luminous transmittance (85.7%) enables efficient sunlight screening in hot weather and clear vision in cool weather. Such 'smart windows' remain stable for over 10,000 heating/cooling cycles. These combined features indicate the hydrogel suitability for applications ranging from heat-modulating smart windows (architectural, automotive, etc.) to passive temperature indicators and even wearables.

Damping technologies aim to control the loads and deformations generated by ambient or forced vibrations in structures and machineries used in transport applications and construction. Traditionally, the materials used in damping devices are of fossil origin, but viscoelastic biobased resources are an alternative source of damping materials. Here, we develop an alginate-based hydrogel system with diverse porosity topologies by including poloxamer 407 as a sacrificial porogen at varying concentrations. Vibration transmissibility tests and dynamic mechanical analysis reveal these gels exhibit loss factors between 16% and 28% in the 100-300 Hz frequency range and that the dynamic modulus increases over an order of magnitude compared to the static modulus, reaching approximately 3 MPa. The visco- and poroelastic and pneumatic-like effects from the tunable porous structures contribute significantly to this damping effect. Furthermore, these hydrogels are biosourced and biodegradable, providing a sustainable alternative to conventional fossil-based damping materials.

The chemical and electronic properties of surfaces and interfaces are important for many technologically relevant processes, be it in information processing, where interfacial electronic properties are crucial for device performance, or in catalytic processes, which depend on the types and densities of active nucleation sites for chemical reactions. Quasi-periodic and nonperiodic crystalline surfaces offer new opportunities because of their inherent inhomogeneity, resulting in localisation and properties vastly different from those of surfaces described by conventional Bravais lattices. Here, we demonstrate the formation of a nonperiodic tiling structure on the surface of the frustrated antiferromagnet PdCrO₂ due to hydrogen adsorption. The tiling structure exhibits no long-range periodicity but comprises few-atom hexagonally packed domains covering large terraces. Measurement of the local density of states by tunnelling spectroscopy reveals adsorption-driven modifications to the quasi-2D electronic structure of the surface layer, showing exciting opportunities arising from electron localisation.