Molecular hydrogen (H2), once regarded as a biologically inert gas, has recently emerged as a chemically active mediator with unique redox selectivity and excellent biocompatibility. In contrast to conventional gas administration, the biomedical efficacy of H2 is fundamentally governed by its chemical generation pathways, reaction kinetics, and spatiotemporal controllability. Recent advances in chemistry-driven H2 production-encompassing electrocatalytic, photocatalytic, sonocatalytic, piezocatalytic, chemical reaction-based, and biohybrid approaches-have enabled precise regulation of hydrogen generation at interfaces and within complex biological environments. These chemically controlled strategies enable selective regulation of highly reactive oxygen and nitrogen species. Beyond direct radical modulation, the generated hydrogen further regulates inflammatory signaling, mitochondrial homeostasis and immune responses, and ultimately remodels pathological microenvironments linked to inflammation, cancer, impaired wound healing and tissue degeneration. In this Review, we systematically summarize the chemical principles underlying H2 bioactivity and critically analyze reaction mechanisms and material design strategies for controlled H2 generation. Emphasis is placed on the chemical-biological coupling processes that translate molecular-scale reactions into macroscopic therapeutic outcomes. Finally, current challenges and future opportunities are discussed from a chemistry-centered perspective, highlighting the role of reaction engineering and chemical controllability in advancing hydrogen-based biomedical applications.

ABSTRACT The in vitro engineering of vascularized cardiac tissues holds transformative potential for disease modeling, drug screening, and regenerative therapy. However, despite rapid advances in stem cell biology, biomaterials, and biofabrication technologies, the reconstruction of functional, perfusable vasculature within engineered myocardial tissues remains a central and unresolved challenge. In this review, we move beyond a descriptive catalog of available techniques and instead present a process‐oriented framework for understanding vascularized cardiac tissue engineering. By systematically analyzing how cellular components, biomaterial design, and biofabrication strategies collectively govern vascular formation, perfusion stability, and myocardial function, we examine self‐assembly, mold‐casting, 3D bioprinting, and microfluidic approaches, to critically evaluate their respective advantages and trade‐offs under cardiac‐specific physiological constraints. Finally, application prospects of vascularized cardiac tissues in disease modeling and drug testing are discussed, and current limitations and future directions are proposed to accelerate translational impact. By reframing vascularized cardiac tissue engineering as an integrated manufacturing challenge rather than a collection of isolated technologies, this review aims to provide a coherent conceptual guide for advancing functional human cardiac models.

Bioactive wound dressings capable of actively directing skin regeneration rather than merely protecting damaged tissue have long been a central goal in regenerative biomaterials, and a recent report by Juanes-Gusano et al. in Cell Biomaterials brings us closer to that goal. Using elastin-like recombinamer hydrogels functionalized with laminin-derived peptides via click chemistry and recombinant engineering, the authors created an extracellular matrix (ECM)-mimetic matrix that enhances skin-cell adhesion, migration, and re-epithelialization.

Understanding the migration of metal clusters within amorphous matrices and crystallization dynamics is fundamental to tailoring interface reactions and designing material functionalities. Despite extensive advances in metal-induced crystallization, the atomistic dynamic pathways and microscopic mechanisms of metal long-range diffusion on disordered matter remain elusive. Here, we employ atomic-resolution in situ heating transmission electron microscopy, integrated with density functional theory calculations, to systematically investigate the Au cluster long-range diffusion on amorphous silicon (a-Si) and the simultaneous resulting crystallization mechanism at the atomic scale. Amorphous Au clusters follow Arrhenius-type diffusion kinetics with an activation energy barrier of approximately 0.69 eV, notably without the formation of any intermediate metal silicide. Our dynamic observations reveal two synergistic diffusion modes: linear homogeneous diffusion and nonlinear aggregation-spreading, fundamentally driven by the higher diffusion barrier on the amorphous surface compared to its crystalline counterpart. These results offer atomic-scale evidence for Au surface diffusion and its role in mediating crystallization, thereby providing a pathway for exploring surface diffusion dynamics at amorphous-amorphous/crystalline interfaces.

Bacterial infections remain a critical challenge in wound care, demanding advanced multifunctional materials for effective treatment. Here, this work presents a 3D‐printable hydrogel (STFWA) integrating a Schottky heterojunction and dual‐network architecture for synergistic photothermal and photodynamic antibacterial therapy. The hydrogel incorporates W18O49‐x@Au nanostructures, where Au nanoparticles are in situ grown on oxygen‐deficient W18O49‐x (bandgap ≈1.5 eV), forming a Schottky junction that enhances carrier separation and reactive oxygen species (ROS) generation. The dual‐network matrix, composed of silk fibroin and tannic acid‐Fe3+ (TA/Fe3+), exhibits robust mechanical integrity and hemostatic capability, while silk fibroin enables high‐resolution digital light processing (DLP) 3D printing. The co‐existence of W18O49‐x and Au induces dual localized surface plasmon resonance (LSPR), while TA/Fe3+ contributes to deep coloration, collectively boosting photothermal conversion. Upon near‐infrared (NIR) irradiation, the hydrogel exhibits potent antibacterial efficacy against Staphylococcus aureus and Escherichia coli through combined photothermal and photodynamic mechanisms. In vivo studies using a rat model of infected wounds demonstrate accelerated healing, enhanced angiogenesis, and regulated inflammation. This work highlights a nanostructure‐enabled hydrogel platform for NIR‐activated, synergistic antibacterial therapy with clinical potential in infected wound management.

Large-scale ultraviolet photodetectors are highly promising for detection of weak signals and have the potential for widespread applications in high-tech areas such as aerospace detection and wearable devices. However, the commonly used window electrodes lack transparency to ultraviolet light. Although ultraviolet photodetectors based on Ag nanowires exhibit good response due to their broad transparency range, the sharp interface between the Ag nanowires and the semiconductor renders them extremely unstable. Surface protection is considered to enhance the stability and lifespan of these devices. Our research has revealed that amorphous Ga2O3 can fully encapsulate the surface of Ag nanowires and securely affix it to the NiO film, resulting in a stable performance with a high responsivity of 48 mA W−1 and detectivity of 6.1 × 1011 Jones for 254 nm light. The unpacked device exhibited a stable photocurrent, showing only 6.8% degradation after 3 months in ambient air. Finally, a large-scale (5 cm × 4 cm, with 12 cm2 of active area) ultraviolet photodetector with a Ga2O3-protected Ag nanowire electrode was prepared, which demonstrated a milliamp-level photocurrent under weak ultraviolet illumination that can be directly read by a conventional multimeter in practical scenarios, indicating the promising prospects of this device for future commercial applications.

Relaxor ferroelectric (RFE) films represent promising candidates for high-performance energy storage applications for miniaturized electronic devices and power systems. However, achieving substantial energy storage performance always involves complex component or structural design. Herein, we employed a nanocomposite approach to obtain ultrahigh-efficiency and robust energy density in simple BaTiO3-based lead-free films. Our lead-free composition of simple (1-x)BaTiO3-xCeO2 (0.0 ≤ x ≤ 0.5) contains only four elements (Ba, Ti, Ce and O). The incorporation of stiff and insulating CeO2 nanocomposites within BaTiO3 matrix could disrupt the long-range-ordered micrometer-size domains into short-range-ordered nanodomains. This disruption suppresses hysteresis and delays polarization of BaTiO3 films. Combined with the enhanced breakdown strength, this formulation yielded an ultrahigh efficiency of ≈90% and a robust energy density of 45 ± 3 J cm-3 at CeO2 contents of x = 0.3 and 0.4. Meanwhile, these two films with x = 0.3 and 0.4 exhibit superior frequency (50 Hz to 2 kHz) and thermal stability (20 °C to 120 °C), demonstrating stable energy storage performance. The proposed strategy opens up a new avenue for designing high-performance nanocomposite films by incorporating stiff secondary phase embedded in BaTiO3 or even linear SrTiO3 dielectrics.

Mitophagy alleviates intervertebral disc degeneration (IVDD) by suppressing cGAS-STING and NLRP3 inflammasome-mediated pyroptosis pathways; however, its metabolic regulatory mechanism remains unexplored. Herein, we discovered that mitophagy activator TJ0113 drives metabolic reprogramming characterized by substantially reduced lactate production in senescent nucleus pulposus (NP) cells. This decline directly diminishes histone H3 lysine 18 lactylation (H3K18la), consequently suppressing transcription of the pro-inflammatory gene thrombospondin-1 (THBS1) and blocking downstream inflammatory cascades in IVDD progress. Through combined genetic silencing of THBS1 and pharmacological inhibition of lactate generation, we establish the lactate-H3K18la-THBS1 axis as the essential mechanism mediating mitophagy's anti-inflammatory effects. Our work provides the first evidence that mitophagy orchestrates a metabolic-epigenetic regulatory axis (lactate-H3K18la-THBS1), unveiling novel therapeutic targets for IVDD and paving the way for epigenetic therapies against disc degeneration.

The unique advantages and potential of high-entropy nanoalloys in catalysis are reflected in their ability to transcend the limitations of conventional single-component catalysts through elemental synergies. Herein, an electrocatalyst was synthesized via the microwave rapid heating method, consisting of FeCoNiRuPt high-entropy alloy nanoparticles supported on reduced graphene oxide. The electrocatalytic hydrogen evolution reaction performance of this sample in acidic and alkaline solutions significantly surpasses that of the commercial 20% Pt/C catalysts. Moreover, its oxygen evolution reaction performance in alkaline solution outperforms commercial IrO2 catalysts. Microstructural characterization indicates that the superior hydrogen evolution reaction activity is attributed to enhanced electron transfer and surface element concentration gradients induced by the dissolution of transition metals during catalysis. For the oxygen evolution reaction, the performance enhancement is ascribed to the formation of a stable high-entropy oxyhydroxide layer on the alloy surface. Stability tests confirm that the catalyst maintains consistent performance for over 120 hours under both acidic and alkaline conditions. These findings highlight the significant potential of high-entropy alloys as bifunctional catalysts for efficient electrochemical water splitting.

Stem cells hold great promise for repairing degenerated nucleus pulposus (NP) in intervertebral disc degeneration (IVDD) via differentiating into NP-like cells and replenishing the extracellular matrix (ECM). However, the harsh environment in degenerated NP contributes to poor survival, low differentiation efficiency, and matrix catabolism, hampering stem cells' long-term transplantation and efficacy. Herein, a hyaluronic acid (HA)-based hydrogel (Pep-aGel) functionalized with collagen mimetic peptide and amination is fabricated to deliver glycoengineered stem cells for NP repair. The peptide (GFOGER), which contains the integrin recognition sequence of collagen, is selectively bound to the upregulated integrin-β1 of glycoengineered stem cells, thereby promoting their NP-like differentiation. The amination introduced amino groups in hydrogel and further enhanced the integration of cell-secreted glycosaminoglycans (GAGs) on the HA chains, which mimicked the biosynthesis of Aggrecan, creating an NP-like nanostructure in the hydrogel. Pep-aGel loading with glycoengineered cells showed injectable properties and significantly improved disc height, extracellular matrix content, and GAG deposition in rat degenerated discs. This approach established a self-sufficient system that consists of NP cell replenishment, in situ ECM supply, and GAG anchoring, which may offer a concise, yet synergistic, strategy for the regeneration of IVDD.

Materials derived from cellulose have attracted considerable attention as affordable substrates for solar desalination, contributing to the solution of the worldwide water crisis. These substances allow for exact control of structural features and improve light absorption in photothermal processes, promoting specific interactions between light scattering and reflection within their porous structure. Moreover, cellulose can be readily transformed into nano- and microporous forms, which enhances water transportation due to its inherent three-dimensional properties. This review examines the design and utilization of cellulose-based solar evaporators for desalination purposes. With benefits such as biocompatibility, environmental friendliness, economic viability, renewable nature, sustainability, and versatility for diverse designs, cellulose-derived materials are set to play a vital role in addressing global water issues.

With the growing demand for high-performance computing in deep learning, energy-efficient analog computing has emerged as a promising alternative to conventional energy-intensive digital processing. A major obstacle in this field is the physical realization of activation functions, due to the lack of analog f (FETs) that inherently exhibit the desired piecewise-linear transfer characteristics. Here, a novel strategy is presented for implementing the Rectified Linear Unit (ReLU) activation function by exploiting the high density of states (DOS) associated with van Hove singularities (vHs), induced by flat bands in a kagome semiconductor Nb3Cl8 FET. This vHs-enhanced DOS imparts pronounced piecewise-linear transfer behavior at low temperatures, effectively mimicking the ReLU function. To enable room-temperature operation, the origin of the hysteresis commonly observed in Nb3Cl8 FETs is identified and addressed. Temperature-dependent and time-resolved measurements attribute the hysteresis to charge trapping at the Nb3Cl8-substrate interface. By introducing a hexagonal boron nitride (h-BN) buffer layer, the hysteresis is successfully suppressed, achieving stable and highly linear transfer characteristics at room temperature. These results demonstrate the potential of vHs-engineered electronic states for the physical implementation of analog activation functions, offering a pathway toward compact, high-density, and energy-efficient hardware for analog deep learning accelerators.

Freckles formed during directional solidification of single-crystal nickel-based superalloys reduced the mechanical properties of turbine blades, posing a significant challenge to the manufacturing of high-quality colossal single-crystal gas turbine blades. However, the mechanism of the formation and distribution of freckles in large-sized blades remain unclear, and prior interpretation of freckle formation by dendrite fragmentation has not been empirically confirmed. Here the constitutional supercooling-induced freckle nucleation mechanism in large-sized blades of heavy-duty gas turbines during directional solidification was investigated. Rather than utilizing simple-structure samples or small-sized samples, casting experiments on 300 mm large-sized blades, composed of five typical single-crystal/directional superalloys (GTD111DS, 247LCDS, RenéN4, RenéN5, and CMSX-4), were conducted. Numerical analysis of the real experiment data demonstrates a noteworthy law consistent with the principles of solidification thermodynamics: alloys with lower critical constitutional supercooling thresholds tend to form more freckles, which matches the freckle formation tendency obtained from the experiment: CMSX-4 > RenéN5 > 247LCDS > RenéN4 > GTD111DS. To unravel the mechanism, we conduct advanced multi-component, coupled-field dendrite growth simulations based on the phase-field–lattice Boltzmann model. The results indicate that the necessary information for judging freckles during dendrite growth simulation, such as element segregation, and dendrite orientation, are exceedingly consistent with the measured values in the experiments. The constitutional supercooling-induced freckle formation mechanism under low temperature gradient condition for large-size blades was revealed.

This work reports the development of an advanced multifunctional hydrogel system designed to address the challenges of infectious wound healing and tissue regeneration. We constructed a polyvinyl alcohol-borax/GelMA hybrid hydrogel matrix, endowing the photocurable hydrogel with excellent mechanical properties and self-healing capability. Bacterial cellulose (BC), a naturally derived biopolymer synthesized by specific microbial strains, was incorporated into the hydrogel matrix to enhance its mechanical properties, structural stability, and biocompatibility, while also serving as a scaffold for cellular adhesion and proliferation. Additionally, the hydrogel was functionalized with tannic acid (TA)-modified MXene nanosheets, which imparted superior antibacterial efficacy and enabled photothermal therapy under near-infrared (NIR) light irradiation. In vitro evaluations confirmed the hydrogel's excellent biocompatibility and antibacterial performance, while in vivo studies demonstrated its ability to significantly accelerate the healing of infectious wounds. This was achieved by effectively reducing bacterial load, promoting tissue regeneration, and alleviating local inflammation under NIR irradiation. These findings highlight the potential of this BC-based hydrogel system as a robust platform for combating bacterial infections, facilitating wound healing, and supporting tissue regeneration in the context of complex skin injuries.

Mitochondrial dysfunction plays a pivotal role in intervertebral disc degeneration (IVDD) by disrupting mitochondrial bioenergetic balance, which leads to impaired ATP synthesis, accumulation of ROS, degradation of the extracellular matrix, and degeneration of nucleus pulposus cells. Despite advances in single or multiple therapeutic strategies, a more comprehensive and coupled cascade regulation strategy that fundamentally restores mitochondrial function is urgently needed, but rarely reported. Mitochondrial bioenergetics is cascade-regulated by the interplay between the OXPHOS and the TCA cycle, where impairment of either disrupts energy homeostasis, necessitating coordinated cascade therapeutic intervention. Hence, mitochondria-targeting polymeric micelles (AKG@PIDE-OPDEA) were constructed via self-assembly of an amphiphilic polymer (PIDE-OPDEA) and α-ketoglutarate (AKG). AKG@PIDE-OPDEA enabled a synergistic mitochondrial repair approach by addressing both the "raw materials" (AKG supply) and the "production line" (mitochondrial respiratory function). Through this concatenation-like therapy, AKG@PIDE-OPDEA restores the mitochondrial bioenergetics in degenerated NPCs and alleviates ECM degradation. In terms of mechanism, it restrains mitochondrial hyperfragmentation and mitigates mitochondrial matrix swelling, which effectively limit stress-induced mtDNA leakage, subsequently inhibiting cGAS-STING pathway activation and reducing downstream inflammation. Overall, this study demonstrates the feasibility of an intramitochondrial energy chain therapy, offering a novel strategy for the treatment of IVDD.

Circular RNAs (circRNAs) play a critical regulatory role in degenerative diseases; however, their functions and therapeutic applications in intervertebral disc degeneration (IVDD) have not been explored. Here, we identified that a novel circATXN1 highly accumulates in aging nucleus pulposus cells (NPCs) accountable for IVDD. CircATXN1 accelerates cellular senescence, disrupts extracellular matrix organization, and inhibits mitochondrial respiration. Mechanistically, circATXN1, regulated by heterogeneous nuclear ribonucleoprotein A2B1-mediated splicing circularization, promotes progerin translocation from the cell nucleus to the cytoplasm and inhibits the expression of insulin-like growth factor 1 receptor (IGF-1R). To demonstrate the therapeutic potential of circATXN1, siRNA targeting the backsplice junction of circATNX1 was screened and delivered by tetrahedral framework nucleic acids (tFNAs) due to their unique compositional and tetrahedral structural features. Our siRNA delivery system demonstrates superior abilities to transfect aging cells, clear intracellular ROS, and enhanced biological safety. Using siRNA–tFNAs to silence circATXN1, aging NPCs exhibit reduced mislocalization of progerin in the cytoplasm and up-regulation of IGF-1R, thereby demonstrating a rejuvenated cellular phenotype and improved mitochondrial function. In vivo, administering an aging cell-adapted siRNA nucleic acid framework delivery system to progerin pathologically expressed premature aging mice (zmpste24−/−) can ameliorate the cellular matrix in the nucleus pulposus tissue, effectively delaying IVDD. This study not only identified circATXN1 functioning as a cell senescence promoter in IVDD for the first time, but also successfully demonstrated its therapeutic potential via a tFNA-based siRNA delivery strategy.

Freckles, one of the common defects in blades used in heavy-duty gas turbines, hugely deteriorate the mechanical properties and liability of blades under service conditions. The thermal-solutal convection theory is a widely adopted formation mechanism, but few solid experimental pieces of evidence have been reported. Here, the grain microstructure in freckle chains taken from four different Nickel-based superalloys with either single-crystal or directionally solidified alloy is analyzed for the first time. The relationship between the internal stress and the misorientation throughout the freckle chains is studied by means of state-of-the-art electron microscopy. The results supply new experimental evidence of the thermal-solutal convection theory, which is further supported by the fact that borides at the boundary are randomly orientated to alloys. Therefore, this research enriches the methodology of freckle study, providing new insight into the formation mechanism of casting defects.