Materials Horizons最新文献

This study investigates the field-induced ferroelectric (FFE) characteristics and dynamic random access memory (DRAM) performance of Y-doped Hf_0.5Zr_0.5O₂ (Y:Hf_0.5Zr_0.5O₂) thin films grown by atomic layer deposition (ALD). Compared with undoped Hf_0.5Zr_0.5O₂, the Y:Hf_0.5Zr_0.5O₂ film exhibited suppressed ferroelectric orthorhombic phase and stabilized FFE tetragonal phase, resulting in double hysteresis loop characteristics in the polarization-electric field curves. These changes were attributed to substitutional diffusion of Y ions introduced by a single ALD cycle of Y₂O₃ inserted in the middle of the film. However, the onset field of the FFE effect from the pristine film was too high for DRAM application. To address this issue, a stepwise cycling method was proposed, consisting of an initial short high-field cycling step (6 MV cm^-1, 10⁵ cycles, 1 second) followed by subsequent cycles at gradually decreased field amplitudes (5 MV cm^-1, 10⁵ cycles, 1 second → 4 MV cm^-1, 10⁷ cycles, 100 seconds). This approach effectively shifted the FFE switching peaks toward lower fields, enabling charge boosting at low voltage (±0.8 V) while minimizing increases in remanent polarization and leakage current density (J). Consequently, the stepwise cycled 5.5-nm-thick Y:Hf_0.5Zr_0.5O₂ film achieved a high dielectric permittivity (k) of ∼68 and a record-low equivalent oxide thickness (EOT) of ∼0.31 nm among dielectric thin films satisfying the DRAM J criterion (J < 10^-7 A cm^-2 at 0.8 V). The substantial EOT reduction with stepwise cycling was enabled by the low-voltage charge-boosting effect, which enhanced the field-induced polarization response. These improvements were attributed to dopant-induced local structural inhomogeneity and effective redistribution of double positively charged oxygen vacancies. The EOT values were sustained with only slight degradation over 10⁹ cycles of 0.8 V operation and fully recovered after short high-field cycling.

To promote the co-delivery of antigens and adjuvants into antigen-presenting cells (APCs) is vital for whole cell vaccine-based immunotherapy. The purpose of this work was to design a novel whole cell vaccine by functionalizing the surface of cancer cells with polyvalent CpG (PCpG) oligodeoxynucleotides through nucleic acid assembly and hybridization. The PCpG-engineered vaccine was successfully prepared with a high CpG loading (3-fold increase) on the cell surface. The vaccine could be internalized efficiently by dendritic cells (DCs), enhancing the maturation of DCs with the expression of antigens and cytokines at a higher level compared to the native vaccine. In a mouse model, locally administered PCpG-engineered whole cell vaccines provoked potent immune stimulation in terms of antigen expression of DCs and T cells in lymphoid tissues. Eventually, tumor growth and lung metastasis were inhibited efficiently. Notably, while we demonstrated the display of CpG, many other ligands can be used as substitutes of CpG. Therefore, this work opens a new pathway to develop a whole cell vaccine.

Tissue engineering is an emerging and integrated field for the repair of defective tissues, which benefits from the interdisciplinary development of biomaterial and engineering techniques. Electrospinning is a promising technique used in tissue engineering to fabricate fiber-based biomaterials that could mimic the extracellular matrix even at the nanometer level, but there has been no review to identify the trends and systematically summarize the application strategies of electrospinning in tissue engineering. This review initially used bibliometric analysis to investigate the trends of electrospinning in tissue engineering from the beginning of this century by evaluating distinctive aspects including publication years, countries, institutions, and keywords. Then, this review presents the multi-hierarchical strategies used in electrospinning to fabricate functional scaffolds for tissue engineering, including biochemical modification, biophysical modification and cell incorporation. Moreover, the hybrid combinations of electrospinning with other biofabrication techniques to fabricate composite scaffolds are summarized including textile, 3D printing, hydrogel, lyophilization and gas foaming, thus finely simulating the bionic 3D microenvironment or the complex/interfacial tissue structures. Finally, this review discusses the research prospects and ongoing challenges, aiming to promote further development and clinical transformation.

Origami-inspired structures provide unprecedented opportunities for creating lightweight, deployable systems with programmable mechanical responses. However, their design remains challenging due to complex nonlinear mechanics, multistability, and the need for precise control of deployment forces. Here, we present a physics-informed neural network (PINN) framework for both forward prediction and inverse design of conical Kresling origami (CKO) without requiring pre-collected training data. By embedding mechanical equilibrium equations directly into the learning process, the model predicts complete energy landscapes with high accuracy while minimizing non-physical artifacts. The inverse design routine specifies both target stable-state heights and separating energy barriers, enabling freeform programming of the entire energy curve. This capability is extended to hierarchical CKO assemblies, where sequential layer-by-layer deployment is achieved through programmed barrier magnitudes. Finite element simulations and experiments on physical prototypes validate the designed deployment sequences and barrier ratios, confirming the robustness of the approach. This work establishes a versatile, data-free route for programming complex mechanical energy landscapes in origami-inspired metamaterials, offering broad potential for deployable aerospace systems, morphing structures, and soft robotic actuators.

The development of systems that can efficiently store and manage thermal energy - i.e., heat - would improve the efficiencies of numerous processes throughout multiple sectors of the global economy. Nevertheless, the development of these thermal storage devices remains at a relatively early stage. To engage more researchers in the development of these devices and to accelerate their commercialization, this review presents an introduction to the properties of thermal storage materials that absorb and release heat through thermochemical reactions. Thermochemical materials typically exhibit the largest energy densities among all approaches to material-based heat storage. Nevertheless, they suffer from limited reaction rates and poor cycle life. An additional challenge is the multiscale nature of the energy storage process, which ranges from atomistic interactions that govern the storage of heat through alteration of chemical bonds, to mesoscale processes that control the transport of mass and heat. Following an overview of general concepts related to thermal energy storage, emphasis is placed on describing properties relevant for low-temperature applications. These applications include domestic heat storage/amplification (hot water heating), adsorptive cooling (air conditioning), and heat-moisture recuperation. Subsequently, detailed introductions are provided to the mechanisms and materials relevant for the three primary approaches to low-temperature thermochemical storage, including: (i) absorption in solids (hydrates, ammoniates, and methanolates); (ii) adsorption in porous hosts (zeolites, metal-organic frameworks); and (iii) dilution in liquids. For each category, advantages and shortcomings of benchmark and emerging materials are discussed. Finally, challenges and opportunities are highlighted for research aimed at developing optimal materials for thermochemical energy storage.

Shining light on a mixed ionic-electronic conductor induces variations in both its electronic and ionic behaviors. While optoelectronic processes in semiconductors with negligible ionic conductivities are well understood, the role of mobile ions in photoactive mixed conductors, such as hybrid halide perovskites, is largely unexplored. Here, we propose a model addressing this problem, combining optoelectronics and optoionics. Using methylammonium lead iodide (MAPI) as a model material, we discuss the expected influence of optical bias on the charge carrier chemistry of mixed conductors under steady-state conditions. We show that changes in the concentration of ionic defects under light with respect to the dark case are a direct consequence of their coupling to electrons and holes through the component chemical potential (iodine in the case of MAPI) and the electroneutrality condition. Based on the trend in the quasi-Fermi level splitting in the mixed conductor, we emphasize implications of controlling point defect chemistry for the function and performance optimization of solar energy conversion devices, including those based on halide perovskites. Lastly, we show that, in the presence of multiple redox reactions mediating the ionic and electronic quasi-equilibrium, either positive or negative changes in the ionic defect pair chemical potential can be obtained. These findings indicate the intriguing possibility to increase or reduce ionic defect concentrations in mixed conductors through exposure to light.

Conventional hydrogels often fail to simultaneously balance the mechanical resilience, tissue adhesion, and electrical conductivity-key requirements for reliable soft bioelectronic interfaces in monitoring scenarios. In this study, we introduce a conductive nanofibrillar double-network hydrogel adhesive that enables real-time, long-term monitoring of human motion and physiological signals, including electrocardiography (ECG), electromyography (EMG), and lung respiration. The double-network matrix, coupled with silver nanoparticle-doped protein nanofibrils, facilitates tunable mechanical properties, tissue-adhesive characteristics, and electrical conductivity of the structural material. The ultra-sensitive strain responsiveness enables precise and reliable detection of various body movements, from finger bending to subtle vocal cord vibration, as well as real-time monitoring of cardiac activity, muscle contractions, and respiratory patterns. Demonstrations in large animal models illustrate its capabilities in sealing lung injury and long-term monitoring lung activity, enabling early detection of abnormalities and facilitating potential personalized healthcare interventions in clinical settings.

The radical anion of amide-functionalized perylene diimide (TFPDIOH˙^-) aggregates into a pimer that is stabilized through pancake bonding. In the presence of primary amines, this pimer can undergo disaggregation, offering potential for responsive organic sensors. In this study, density functional theory calculations were employed to elucidate the sensing mechanism, which can be represented as follows: 1/2[TFPDIOH]₂^2- + nBuNH₂ → [nBuNH₂·TFPDIOH]˙^-. Computational results reveal that steric hindrance from the bulky substituents on the amide positions weakens π-stacking interactions, thereby allowing strong hydrogen bonding to induce pimer disaggregation. The phenolic hydroxyl group on the substituent forms a low-barrier hydrogen bond (LBHB) with nBuNH₂, which is characterized by a short N⋯O distance, high ρ_BCP, 3c-4e bonding pattern, and nearly barrierless proton transfer. The electron-withdrawing fluorine atoms on the substituent enhance hydroxyl acidity, further stabilizing LBHB formation. These findings reveal the LBHB-driven disaggregation mechanism and demonstrate that the rational combination of pancake bonding and LBHB interactions offers a novel strategy for developing π-radical-based organic sensors with enhanced sensitivity.

Hydrogen sulfide (H₂S), a gaseous signaling molecule with multiple cardioprotective effects, has attracted considerable attention for treating myocardial infarction (MI), a leading global cause of death. However, its ultrashort half-life (seconds to minutes) and the extended recovery required for myocardial repair pose substantial challenges to therapeutic efficiency, emphasizing the urgent need for month-level controlled H₂S delivery strategies, an endeavor still unresolved. Inspired by natural trisulfide H₂S donors, we introduce a novel disulfide/trisulfide cross-linked network derived from natural lipoic acid (LA) and its trisulfide derivative LATS, engineered as a drug-carrier homologated cardiac patch (Fe@LA/LATS) for MI therapy. Fe@LA/LATS adheres firmly to wet cardiac tissue, providing a stable mechanical support while undergoing thiol-responsive depolymerization to release LA and H₂S. In situ-released LA scavenges reactive oxygen species (ROS) and attenuates the inflammatory response around the infarcted myocardium. Concurrently, H₂S significantly stimulates cardiomyocyte proliferation and angiogenesis, further accelerating myocardial regeneration and functional recovery. Impressively, Fe@LA/LATS containing 5% LATS ensures a controlled release of H₂S at therapeutically effective levels for 1 month, with a seamless release process until complete degradation. This new strategy dramatically enhances the overall therapeutic efficiency, exhibiting promising potential for further applications.

Correction for ‘Hydrophobic eutectogels with heterostructure for wearable sensing and undersea alarms’ by Wenna Wu et al., Mater. Horiz., 2025, https://doi.org/10.1039/d5mh01437a.