http://onlinelibrary.wiley.com/rss/journal/10.1002/(ISSN)1521-4095

Upconversion nanoparticle-covalent organic framework core–shell particles provide enhanced contrast for optoacoustic imaging by leveraging the optical absorption of upconversion luminescence within the covalent organic framework matrix. Beyond their role as contrast agents, these particles enable customizable therapeutic agent loading and release, as well as magnetic microrobotic steering within vascular environments.

Despite the development of various medical imaging contrast agents, integrating contrast signal generation with therapeutic and microrobotic functions remains challenging without complicated fabrication processes. In this study, upconversion nanoparticle-covalent organic framework (UCNP-COF) core–shell sub-micron particles are developed that function as therapeutic microrobots trackable with multi-spectral optoacoustic tomography (MSOT) imaging and can be loaded with desired therapeutic molecular agents in a customizable manner. The mechanism of optoacoustic signal generation in UCNP-COF particles is attributed to the quenching of upconversion luminescence emitted by the UCNPs, which is absorbed by the encapsulating COF and subsequently converted into acoustic waves. Unlike other microparticulate agents previously imaged with MSOT, UCNP-COF particles do not pose concerns about their stability and biocompatibility. Simultaneously, the mesoporous texture of the COF provides a large surface area, allowing for the efficient loading of various drug molecules, which can be released at target sites. Furthermore, the magnetic UCNP-COF Janus particles can be magnetically navigated through in vivo vasculature while being visualized in real-time with volumetric MSOT. This study proposes an approach to design photonic materials with multifunctionality, enabling high-performance medical imaging, drug delivery, and microrobotic manipulation toward their future potential clinical use.

A strongly coupled multisite anode electrocatalyst with cluster-scale ruthenium-tungsten oxide (Ru-WOx) interface is developed for alkaline anion exchange membrane fuel cells (AEMFCs), which could simultaneously achieve high coverage of hydroxyl (OHad) and hydrogen (Had) at Ru and WOx domains, respectively. The AEMFC delivers a high peak power density of 1.36 W cm−2 with a low anode catalyst loading of 0.05 mgRu cm−2 and outstanding durability.

Ruthenium (Ru) is a more cost-effective alternative to platinum anode catalysts for alkaline anion-exchange membrane fuel cells (AEMFCs), but suffers from severe competitive adsorption of hydrogen (Had) and hydroxyl (OHad). To address this concern, a strongly coupled multisite electrocatalyst with highly active cluster-scale ruthenium-tungsten oxide (Ru-WOx) interface, which could eliminate the competitive adsorption phenomenon and achieve high coverage of OHad and Had at Ru and WOx domains, respectively, is designed. The experimental and theoretical results demonstrate that WOx domain functions as a proton sponge to perpetually accommodate the activated hydrogen species that spillover from the adjacent Ru domain, and the resulting WO-Had species are readily coupled with Ru-OHad at the heterointerface to finish the hydrogen oxidation reaction with faster kinetics via the thermodynamically favorable Tafel-Volmer mechanism. The AEMFC delivers a high peak power density of 1.36 W cm−2 with a low anode catalyst loading of 0.05 mgRu cm−2 and outstanding durability (negligible voltage decay over 80-h operation at 500 mA cm−2). This work offers completely new insights into understanding the alkaline HOR mechanism and designing advanced anode catalysts for AEMFCs.

The heart organoid model exhibits the acidic microenvironment characteristic of myocardial infarction, which emerges as a pivotal force propelling the movement of micro-robots. These micro-robots, administered through microneedles, can penetrate deep into the tissue, effectively delivering therapeutic payloads to facilitate heart repair.

Post-myocardial infarction (MI), the rapid decrease in pH triggers myocardial cell acidosis, which compromises the therapeutic efficacy of exosomes in MI. The groundbreaking research in the human cardiac organoid MI model suggests that exosomes, when paired with pH adjustment, dramatically reduce cardiomyocyte mortality while maintaining their proliferative potential, underscoring the importance of pH regulation in myocardial preservation. Micro-robot mounted micro-needle (MN) patch is thus proposed, targeting MI-acidic microenvironmet, to deliver exosomes into deep injured tissue. Upon injection, the patch base releases VEGF-laden nanoparticles adhering to the infarcted myocardium. The smart patch is found not only 3D reconstructs the vascular network in MI regions but also effectively saves cardiomyocytes in rats. Furthermore, the minimally invasive delivery of MN patches are also verified to hearts of rabbits and pigs via thoracoscopic surgery underscores. These findings suggest that precise regulation of the microenvironment is a key to improving treatment outcomes.

This study proposes tribenzyl organic cation carried multidentate X-type Lewis soft base to enhance adhesion and passivate defects simultaneously, aiming to achieve foldable and efficient perovskite nanocrystal-based light-emitting diodes. The resulting pure red F-PeLEDs exhibit a recorded high EQE of 16.2% and robust mechanical properties to endure 5000 folding cycles with small radius of 1 mm.

Lead-halide perovskite nanocrystals (PNCs) exhibit significant potential for advancing foldable perovskite light-emitting diodes (F-PLEDs) due to their discrete crystalline morphology, bright emission across an extensive color gamut, and remarkable color purity; however, their progression remains in the early stages with the concerns of inadequate performance and mechanical instability. This study proposes a ligand strategy employing tribenzyl organic cation (tribenzylamine, TBA) carried multidentate X-type Lewis soft base (sodium acid pyrophosphate, SAPP) to address the challenges above simultaneously. Specifically, the use of multibranched aromatic ligands considerably improved the adhesion force between PNCs and adjacent layers, enhancing mechanical stability during folding, while the control sample shows deleterious cracks. Additionally, TBA-SAPP ligands effectively eliminate the defects in PNC film, yielding exceptional photoluminescence properties with a near-unity quantum yield. Consequently, the multifunctional ligands improved F-PLEDs to achieve a record-high external quantum efficiency (EQE) of 16.2% compared to the previously reported pure-red flexible PLEDs and display substantially improved spectral and operational stability. Equally important, these devices demonstrate robust mechanical properties, enduring a small folding radius of 1 mm for 5000 cycles. This ligand strategy is anticipated to inspire relevant research in PNCs and promote the realization of highly efficient and mechanically stable F-PLEDs.

The origin of oxygen framework stability is studied by integrating high covalent element Mo into the bulk and surface of ultra-high nickel cathode materials through a one-step method. Mo with strong covalency can suppress Li/Ni antisite defects and reduce Li-O-Li configurations, thus suppressing irreversible phase transition and stabilizing the oxygen framework structure at high voltage.

Ultra-high nickel layered oxides are recognized as promising cathode candidates for high-energy-density lithium-ion batteries due to their enhanced overall capacity and elevated operating voltage. However, the interlayer sliding of transition metal-oxygen octahedra (TMO6) and the instability of lattice oxygen at high voltages for ultra-high nickel oxide cathodes pose significant challenges to their development. Herein, the origin of oxygen framework stability is investigated by incorporating high-covalent element Mo in both bulk and surface using a one-step integrated method for ultra-high nickel cathode material LiNi0.92Co0.08O2. It is revealed that apart from the isolation and protection effect of the Mo-enriched surface layer, the suppression of Li/Ni antisite defects by Mo6+ with strong covalency in the bulk plays a critical role in reducing the configurations of the activated anionic redox reaction and stabilizing the lattice oxygen and oxygen framework structure. Benefiting from this, the reversibility of anionic redox reaction and the stability of oxygen framework is significantly enhanced, enabling more oxidized oxygen to exist in the form of oxygen dimer ions O2n−$O_2^{n - }$ rather than being lost as gaseous O2. Consequently, the modified ultra-high nickel material demonstrates improved diffusion kinetics and optimized electrochemical performance at high voltage.

Acid etching assisted direct upcycling strategy that selectively removals rock-salt phases on the surface of highly degraded LiNi0.5Co0.2Mn0.3O2 and dissociating polycrystalline structure to single crystals simultaneously, facilitating direct repair of its composition and structure via simple solid-state sintering. The regenerated LiNi0.5Co0.2Mn0.3O2 exhibits comparable capacity and more excellent electrochemical stability to commercialized ones.

Direct recycling of cathode materials has attracted phenomenal attention due to its economic and eco-friendly advantages. However, existing direct recycling technologies are difficult to apply to highly degraded layered materials as the accumulation of thick rock-salt phases on their surfaces not only blocks lithiation channels but also is thermodynamically difficult to transform into layered phases. Here, a surface engineering-assisted direct upcycling strategy that reactivates the lithium diffusion channels at the highly degraded cathode surfaces using acid etching explored. Acid can selectively remove the electrochemically inert rock-salt phases on the surface while simultaneously dissociating the degraded polycrystalline structure to single crystals, thereby reducing the thermodynamic barrier of the relithiation process and enhancing the stability of the regenerated cathode. This strategy can restore the capacity of highly degraded LiNi0.5Co0.2Mn0.3O2 from 59.7 to 165.4 mAh g−1, comparable to that of commercialized ones. The regenerated cathode also exhibits excellent electrochemical stability with a capacity retention of 80.1% at 1 C after 500 cycles within 3.0–4.2 V (vs graphite) in pouch-type full cells. In addition, the generality of this strategy has also been validated on Ni-rich layered materials and LiCoO2. This work presents a promising approach for direct recycling of highly degraded cathode materials.

A novel 3D printing method enables the fabrication of materials with precisely controlled mechanical properties at nanoscale resolution. A volume-conserving photoresist combined with the free and open-source software, OpenScribe, achieves mechanical transitions over 770 nanometers - representing a 130-fold improvement over existing approaches. This advancement enables the creation of complex materials with unprecedented control over local elasticity.

Fabrication methods that synthesize materials with higher precision and complexity at ever smaller scales are rapidly developing. Despite such advances, generating complex 3D materials with controlled mechanical properties at the nanoscale remains challenging. Exerting precise control over mechanical properties at the nanoscale would enable material strengths near theoretical maxima, and the replication of natural structures with hitherto unattainable strength-to-weight ratios. Here, a method for fabricating materials with nanovoxelated elastic moduli by employing a volume-conserving photoresist composed of a copolymer hydrogel, along with OpenScribe, an open-source software that enables the precise programming of material mechanics, is presented. Combining these, a material composed of periodic unit cells featuring heteromechanically tessellated soft-stiff structures, achieving a mechanical transition over an order-of-magnitude change in elastic modulus within 770 nm, a 130-fold improvement on previous reports, is demonstrated. This work critically advances material design and opens new avenues for fabricating materials with specifically tailored properties and functionalities through unparalleled control over nanoscale mechanics.

A novel non-fullerene acceptor, BFDO-4F, is integrated into organic photodetectors (OPDs) to enable electron trapping. The resulting devices exhibit dual-mode functionality, with bias-switchable operation between photovoltaic (PV) and photomultiplication (PM) modes. An on-chip module is demonstrated, where the PV section supplies bias for the PM section achieving self-powered amplifier-free system, highlighting the potential for multifunctional OPDs in advanced optoelectronic applications.

Photomultiplication-type organic photodetectors (PM-OPDs) provide for signal amplification, ideal for detecting faint light, and simplifying detection systems. However, current designs often suffer from slow response speed and elevated dark current. Conversely, photovoltaic-type organic photodetectors (PV-OPDs) provide fast response and high specific detectivity (D *) but have limited photoresponse. This study presents the synthesis and incorporation of a non-fullerene acceptor, BFDO-4F, into the active layer to introduce trap states for capturing photogenerated electrons. The resulting device exhibits dual-mode characteristic and is bias-switchable between PV and PM-modes. In PV-mode, the OPDs achieve high D * of 1.92 × 10¹2 Jones and a response time of 2.83/4.43 µs. In PM-mode, the OPDs exhibit exceptional external quantum efficiency (EQE) up to 3484% and a D * of up to 1.13 × 10¹2 Jones. An on-chip self-powered module with PV-mode pixels driving a PM-mode pixel is demonstrated, yielding a photocurrent approximately five times higher than the reference device. This approach paves the way for developing multifunctional bias-switchable dual-mode on-chip OPDs, suitable for various applications.

This study constructs a unified supercapacitor database comprising hundreds of MOF electrodes based on constant-potential molecular simulation. The relationships between porous structures and electrochemical performance are thoroughly examined through interpretable machine learning techniques, with molecular insights by analyzing in-pore electrode-ion coordination and ion diffusion. These findings pave the way for the design and optimization of advanced electrode materials.

The development of supercapacitors is impeded by the unclear relationships between nanoporous electrode structures and electrochemical performance, primarily due to challenges in decoupling the complex interdependencies of various structural descriptors. While machine learning (ML) techniques offer a promising solution, their application is hindered by the lack of large, unified databases. Herein, constant-potential molecular simulation is used to construct a unified supercapacitor database with hundreds of metal–organic framework (MOF) electrodes. Leveraging this database, well-trained decision-tree-based ML models achieve fast, accurate, and interpretable predictions of capacitance and charging rate, experimentally validated by a representative case. SHAP analyses reveal that specific surface area (SSA) governs gravimetric capacitance while pore size effects are minimal, attributed to the strong dependence of electrode-ion coordination on SSA rather than pore size. SSA and porosity, respectively, dominate volumetric capacitance in 1D-pore and 3D-pore MOFs, pinnacling the indispensable effects of pore dimensionality. Meanwhile, porosity is found to be the most decisive factor in the charging rate for both 1D-pore and 3D-pore MOFs. Especially for 3D-pore MOFs, an exponential increase in porosity is observed in both ionic conductance and in-pore ion diffusion coefficient, ascribed to loosened ion packing. These findings provide profound insights for the design of high-performance supercapacitor electrodes.

This review summarizes the synthesis of printable photonic materials and devices for both wearable and implantable sensing applications. The challenges of mechanical stability, biocompatibility, and large-scale manufacturing are discussed with proposed strategies. Innovations in high-performance printable photonic sensing devices can inspire their practical applications in personalized medicine and intelligent healthcare.

Photonic materials possess tunable optical properties and have been widely utilized for healthcare applications. These materials enable the detection of physical and physiological bio-signals via modulated optical output characteristics, such as wavelength shifts, fluorescence emission, and light scattering. When further synthesized into functional photonic inks, multimodal devices for epidermal, minimally invasive, and implantable bio-sensing can be constructed in facile and printable manners. This review first introduces functional photonic materials in different geometries and their unique properties. To enable feasible fabrication of multi-functional photonic devices for biosensing in versatile platforms, the synthesis of printable inks and the as-printed devices are then illustrated. Subsequently, the advances and breakthroughs to construct printable photonic devices and integrated systems for wearable and implantable applications are displayed, especially for multimodal sensing to facilitate personalized and remote healthcare. Finally, the challenges in achieving mechanical stability, eliminated degradation, enhanced biocompatibility in dynamic biological environments, and scalable production are discussed, along with the prospects toward reliable and intelligent healthcare.

This work presents a breakthrough in wave manipulation physics and technology, enabling perfect absorption and precise wavefront control. The proposed concept of metagrating surpasses the size and efficiency limitations of conventional ones. Its compact, lightweight design tackles the key challenge inherent to all elastic wave-manipulation metastructures, which consists in the unavoidable vibration modes in finite structures hindering their implementation in real-world applications.

Optical and acoustic metagratings have addressed the challenges of low-efficiency wave manipulation and high-complexity fabrication associated with metamaterials and metasurfaces. In this research, the concept of locally resonant elastic metagrating (LREM) is both theoretically and experimentally demonstrated, which is underpinned by the unique elastic impedance modulation and the hybridization of intrinsic evanescent waves. Remarkably, the LREM overcomes the size limitations of conventional metagratings and offers a distinctive design paradigm for highly efficient, compact, and lightweight structures for wave manipulation in elastic wave systems. Importantly, the LREM tackles a key challenge inherent to all elastic wave-manipulation metastructures, which consists in the unavoidable vibration modes in finite structures hindering their real-world applications.

In this work, a highly scalable chemical approach based on the anion exchange reaction is developed to engineer an amorphous metal compound layer on the surface of argyrodite-type electrolyte grains. Further, a novel localized grain engineering concept is introduced, which combines engineered and pure electrolyte grains to enable aggregates with favorable macroscopic properties for suppressing Li intrusion.

Li intrusion is the primary factor contributing to the undesirable cycling durability and rate capability of all-solid-state lithium metal batteries. However, conventional engineering methodologies for solid electrolytes (SEs) that focus on crystalline scales, such as doping, have limited efficacy in addressing this issue, as they not only involve cumbersome trial-and-error processes but also struggle to simultaneously optimize the multiple macroscopic properties necessary for effectively suppressing Li intrusion. Herein, rather than following the conventional practice of SE engineering, it is concentrated on optimizing SEs at the grain-aggregate level. A highly scalable chemical approach based on a thermodynamic-favored anion exchange reaction is first developed to engineer an amorphous metal compound layer on the surface of argyrodite-type electrolyte grains. Further, a novel localized grain engineering concept is introduced, which combines engineered and pure electrolyte grains to enable aggregates with favorable macroscopic properties for suppressing Li intrusion. The localized grain-engineered electrolyte aggregates greatly enhance Li reversibility and are able to suppress Li intrusion under practical working conditions. Notably, the 20 µm-Li||LiNi0.83Co0.12Mn0.05O2 cell using localized grain-engineered electrolyte aggregates can stably cycle for over 2000 cycles at a high current density of 1.6 mA cm−2.

A novel vapor phase method is first proposed to reconstruct a robust LiF coating layer on the Li-rich Mn-based oxide cathodes. The designed LiF layer effectively modulates the electric field distribution on the electrode surface, thereby promoting the formation of a uniform LiF-rich cathode electrolyte interphase (CEI). The optimized CEI facilitates homogeneous Li+ fluxes on the electrode surface, contributing to a stable electrode-electrolyte interface.

Constructing a stable cathode-electrolyte interphase (CEI) is crucial to enhance the battery performance of Li-rich Mn-based oxide (LMO) cathodes. To achieve an ideal CEI, a gas-phase fluorination technique is proposed to pre-structure a robust LiF layer (≈1 nm) on the LMO surface. The designed LiF layer effectively modulates the electric field distribution on the electrode surface and mitigates undesirable side reactions between the electrode and electrolyte, thereby promoting the formation of a uniform LiF-rich CEI layer on the LMO-F-1. The optimized CEI facilitates homogeneous Li+ fluxes across the electrode surface and enhances Li+ diffusion in the electrode during (de)intercalation, contributing to a stable electrode-electrolyte interface. Moreover, the robust LiF-rich CEI layer effectively suppresses the decomposition of lithium salts in the electrolyte and reduces autocatalytic side reactions triggered by the by-products. In addition, it improves the structural stability of LMO by increasing the formation energies of oxygen and manganese vacancies. As a result, the modified LMO with the LiF-rich CEI retains 95% of its initial capacity after 100 cycles, demonstrating remarkable electrochemical stability. The proposed gas-phase Li+ flux homogenization strategy offers a promising avenue for enhancing the interface stability of high-voltage cathode materials with lithium storage.

The gasotransmitter-nanodonor FSG@AB co-releases hydrogen sulfide (H₂S) and glucose oxidase (GOx) at bone metastases, disrupting mitochondrial function and inhibiting glycolysis to deplete tumor energy sources, exerting robust anti-tumor effects. The released H₂S travels to the anterior cingulate cortex (ACC), upregulating glutamate transporter 1 (GLT-1) expression, reducing extracellular glutamate levels, and mitigating glutamatergic hyperactivity, ultimately alleviating anxiety-like behaviors.

Anxiety is highly prevalent among cancer patients, significantly impacting their prognosis. Current cancer therapies typically lack anxiolytic properties and may even exacerbate anxiety. Here, a gasotransmitter-nanodonors (GND) system is presented that exerts dual anxiolytic and anti-tumor effects via a “tumor-brain axis” strategy. The GND, synthesized by co-embedding Fe2⁺ and S2⁻ ions along with glucose oxidase (GOx) within bovine serum albumin (BSA) nanoparticles (FSG@AB), enables the controlled release of the gasotransmitter hydrogen sulfide (H₂S) in the acidic tumor microenvironment. H₂S and GOx synergistically deplete tumor energy sources, resulting in robust anti-tumor effects. Meanwhile, H₂S generated at the tumor site is transported through the bloodstream to the anterior cingulate cortex (ACC) in the brain, where it modulates neuronal activity. Specifically, in the ACC, H₂S upregulates glutamate transporter 1 (GLT-1), which reduces extracellular glutamate levels and attenuates the hyperactivity of glutamatergic neurons, thereby alleviating anxiety-like behavior. This study proposes a GND system that targets both oncological and psychiatric dimensions of cancer through the “tumor-brain axis” strategy, resulting in improved therapeutic outcomes.

The miniaturized and portable bio-battery, fabricated by 3-D printing of living hydrogels containing electroactive Shewanella oneidensis MR-1 biofilms, represents a novel class of engineered living energy materials. The electricity generated by this device can be harnessed for nerve stimulation to enable precise control over bioelectrical stimulation and physiological blood pressure signals.

Harnessing engineered living materials for energy application represents a promising avenue to sustainable energy conversion and storage, with bio-batteries emerging as a pivotal direction for sustainable power supply. Whereas, the realization of miniaturized and portable bio-battery orchestrating off-the-shelf devices remains a significant challenge. Here, this work reports the development of a miniaturized and portable bio-battery using living hydrogels containing conductive biofilms encapsulated in an alginate matrix for nerve stimulation. These hydrogels, which can be 3-D printed into customized geometries, retained biologically active characteristics, including electroactivity that facilitates electron generation and the reduction of graphene oxide. By fabricating the living hydrogel into a standard 2032 battery shell with a diameter of 20 mm, this work successfully creates a miniaturized and portable bio-battery with self-charging performance. The device demonstrates remarkable electrochemical performance with a coulombic efficiency of 99.5% and maintains high cell viability exceeding 90% after operation. Notably, the electricity generated by the bio-battery can be harnessed for nerve stimulation to enable precise control over bioelectrical stimulation and physiological blood pressure signals. This study paves the way for the development of novel, compact, and portable bio-energy devices with immense potential for future advancements in sustainable energy technologies.

Development of Marine-Degradable Poly(Ester Amide)s

This cover illustrates the development of high-performance poly(ester amide)s (PEAs) for marine-degradable applications. Combining strength and biodegradability, PEAs promise sustainable solutions for fishing gear, reducing ocean plastic pollution with upcycled, eco-friendly materials. More details can be found in article number 2417266 by Hyeonyeol Jeon, Hyo Jeong Kim, Jeyoung Park, Dongyeop X. Oh, and co-workers.

Spin-Orbit-Locking Holography

In article number 2415142, Xiaocong Yuan, Puxiang Lai, Qinghua Song, and co-workers present a multi-channel vectorial holography technique encoded by both the spin and orbital angular momentum using a minimalist, non-interleaved, geometry-phase metasurface. It not only substantially enhances the selectivity of input light, exhibiting intriguing spin-orbit-locking behavior, but also expands the multiplexing channels of the output optical field, holding great potential for advanced light manipulation.

Mechanical Metamaterial

In article number 2410865, Fei Pan, Yuli Chen, and co-workers propose an automatically on-demand reprogrammable mechanical metamaterial. Driven by the pre-established structure-performance relations, the metamaterial can automatically tune its building blocks' states using built-in actuators to match different target stress-strain curves in real time. This offers a new solution for the physical properties reprogramming of artificial systems.

Pixel Circuit Integrated MicroLED

In article number 2416015, Kyungwook Hwang, Hojin Lee, Geonwook Yoo, and co-workers demonstrate advanced technology that will transform the current display industry beyond the backplane limits. The pixel circuit integrated micro-LED (PIMLED) not only incorporates an active-pixel circuit but is also compatible with the intrinsic randomness of fluidic-based transfer technology, ensuring no angular misalignment. The results bring forward scalable, transparent, and form-factor free active-matrix micro-LED display.