Materials Horizons最新文献

The ability of light to manipulate fundamental interactions in a medium is central to research in optomagnetism and applications in electronics. A prospective approach is to create composite quasiparticles, magnetic polarons, highly susceptible to external stimuli. To control magnetic and transport properties by weak magnetic and electric fields, it is important to find materials that support photoinduced magnetic polarons with colossal net magnetic moments. Here, we demonstrate that magnetic polarons with a record-high magnetic moment, reaching and exceeding a hundred thousand Bohr magnetons, can be optically generated in EuO, an archetypal ferromagnetic semiconductor. The phenomenon is established employing the photoinduced Faraday effect studied in EuO films by a two-color pump-probe technique. The giant magnetic polarons are generated just above the Curie temperature once EuO is exposed to photons of an energy exceeding the bandgap. Picosecond temporal dynamics of magnetic polarons follows relaxation processes in the spin-split 5d conduction band occupied by the photoexcited electron. The study is expected to provide a platform for implementation of an efficient optical control over the magnetic state in solids.

Fast development of metallic glass films with high toughness has been a long-sought goal of humankind in view of their superior properties and great potential for application in the field of soft electronics. However, until now, there has been no effective experimental strategy because of the lack of suitable and precise toughness measurement technology. In the present work, we introduced a feasible route for developing tough metallic glass films using combinatorial material library preparation and high-throughput toughness measurement via nanoindentation. Based on this route, tough metallic glass films for the quaternary Zr-Ti-Cu-Al system were successfully screened out. The corresponding electron work function map was detected to uncover the physical mechanism for the composition dependence of toughness. In addition, the preliminary assessments of the screened tough metallic glass films as strain-sensing materials were also conducted. Our current research not only provides a versatile toolbox for high-throughput development of tough metallic glass films, but also exemplifies their potential as strain-sensing materials.

Fabricating tubular hydrogel models with arbitrary structural complexity and controllable diameters using an ultrafast, facile yet universal method is desirable for vascular prototypes yet still a great challenge. Herein, inspired by the denaturing ability of spider silks, a novel strategy to induce complexation via applying highly concentrated alkali into a polyvinyl alcohol/ionic liquid (PVA/IL) solution, i.e., alkali-induced molecular aggregation (AMA), is proposed to achieve such purpose. This strategy enables the rapid and facile fabrication of tubular hydrogel architectures with tunable diameters, controllable thicknesses, and excellent mechanical performance with a tensile strength of up to 1.1 MPa and stretchability exceeding 600%. Importantly, this novel strategy combined with 3D printing facilitates the rapid fabrication of a variety of precise tubular hydrogel models with connected cavity structures which are difficult to achieve using current methods. This ultrafast solidification strategy could also be extended to various alkalis, cations and anions to build different hydrogels, showcasing its versatility and universality. Hence, this strategy can be pioneering to rapidly fabricate complex three-dimensional and hollow enclosed hydrogel models for simulating endovascular interventional therapy.

Given the ongoing requirements for versatility, sustainability, and biocompatibility in wearable applications, cellulose nanocrystal (CNC) photonic materials emerge as excellent candidates for multi-responsive wearable devices due to their tunable structural color, strong electron-donating capacity, and renewable nature. Nonetheless, most CNC-derived materials struggle to incorporate color-changing and electrical sensing into one system since the self-assembly of CNCs is incompatible with conventional conductive mediums. Here we report the design of a conductive photonic patch through constructing a CNC/polyvinyl alcohol hydrogel modulated by phytic acid (PA). The introduction of PA significantly enhances the hydrogen bonding interaction, resulting in the composite film with impressive flexibility (1.4 MJ m^-3) and progressive color changes from blue, green, yellow, to ultimately red upon sweat wetting. Interestingly, this system simultaneously demonstrates selective and sensitive electrical sensing functions, as well as satisfactory biocompatibility, biodegradability, and breathability. Importantly, a proof-of-concept demonstration of a skin-adhesive patch is presented, where the optical and electrical dual-signal sweat sensing allows for intuitive visual and multimode electric localization of sweat accumulation during physical exercises. This innovative interactive strategy for monitoring human metabolites could offer a fresh perspective into the design of wearable health-sensing devices, while greatly expanding the applications of CNC-based photonic materials in medicine-related fields.

Infection is the most prevalent complication of fractures, particularly in open fractures, and often leads to severe consequences. The emergence of bacterial resistance has significantly exacerbated the burden of infection in clinical practice, making infection control a significant treatment challenge for infectious bone defects. The implantation of a structural stent is necessary to treat large bone defects despite the increased risk of infection. Therefore, there is a need for the development of novel antibacterial therapies. The advancement in antibacterial biomaterials and new antimicrobial drugs offers fresh perspectives on antibacterial treatment. Although antimicrobial 3D scaffolds are currently under intense research focus, relying solely on material properties or antibiotic action remains insufficient. Antimicrobial peptides (AMPs) are one of the most promising new antibacterial therapy approaches. This review discusses the underlying mechanisms behind infectious bone defects and presents research findings on antimicrobial peptides, specifically emphasizing their mechanisms and optimization strategies. We also explore the potential prospects of utilizing antimicrobial peptides in treating infectious bone defects. Furthermore, we propose that artificial intelligence (AI) algorithms can be utilized for predicting the pharmacokinetic properties of AMPs, including absorption, distribution, metabolism, and excretion, and by combining information from genomics, proteomics, metabolomics, and clinical studies with computational models driven by machine learning algorithms, scientists can gain a comprehensive understanding of AMPs' mechanisms of action, therapeutic potential, and optimizing treatment strategies tailored to individual patients, and through interdisciplinary collaborations between computer scientists, biologists, and clinicians, the full potential of AI in accelerating the discovery and development of novel AMPs will be realized. Besides, with the continuous advancements in 3D/4D/5D/6D technology and its integration into bone scaffold materials, we anticipate remarkable progress in the field of regenerative medicine. This review summarizes relevant research on the optimal future for the treatment of infectious bone defects, provides guidance for future novel treatment strategies combining multi-dimensional printing with new antimicrobial agents, and provides a novel and effective solution to the current challenges in the field of bone regeneration.

The ever-increasing demand for safe and high-energy-density batteries urges the exploration of ultrathin, lightweight solid electrolytes with high ionic conductivity. Solid polymer electrolytes (SPEs) with high flexibility, reduced interfacial resistance and excellent processability have been attracting significant attentions. However, reducing the thickness of SPEs to be comparable with that of commercial separators increases the risk of short-circuiting. Herein, an ultrathin (≈7 μm), flexible and mechanical robust SPE was constructed from a rationally designed multi-functional polymer network, i.e., poly[2,2,2-trifluoroethyl methacrylate-r-(2-ethylhexyl acrylate)-r-methyl methacrylate-r-1,4-bis(acryloyloxy)butane] (PTEM) and porous polyethylene (PE). The resultant PTEM@PE electrolyte possesses a high tensile strength of 128.0 MPa with extensibility up to 34.8%, which could effectively prevent short-circuiting and minimize the interfacial resistance of cells. The obtained all-solid-state Li|PTEM@PE|LiFePO₄ cell exhibited stable cycling performance over 1500 cycles at 0.5 C with a capacity retention of 74.4%. With high-voltage NCM811 as the cathode, the cell fabricated with PTEM@PE showed a remarkable capacity retention of 84.2% over 500 cycles. Even with the high-mass loading (≈3 mA h cm^-2) NCM811 cathode, the cell could be operated at ambient temperature, demonstrating superior ion-migration kinetics. The current design provides a promising strategy to develop ultrathin and multifunctional solid electrolytes for safe, long-cycling and high-energy-density all-solid-state batteries.

Titanium and its alloys are the most commonly used biometals for developing orthopedic implants to treat various forms of bone fractures and defects, but their clinical performance is still challenged by the unfavorable mechanical and biological interactions at the implant-tissue interface, which substantially impede bone healing at the defects and reduce the quality of regenerated bones. Moreover, the impaired osteogenesis capacity of patients under certain pathological conditions such as diabetes and osteoporosis may further impair the osseointegration of Ti-based implants and increase the risk of treatment failure. To address these issues, various modification strategies have been developed to regulate the implant-bone interactions for improving bone growth and remodeling in situ. In this review, we provide a comprehensive analysis on the state-of-the-art synthetic nanointerfacial bioengineering strategies for designing Ti-based biofunctional orthopedic implants, with special emphasis on the contributions to (1) promotion of new bone formation and binding at the implant-bone interface, (2) bacterial elimination for preventing peri-implant infection and (3) overcoming osseointegration resistance induced by degenerative bone diseases. Furthermore, a perspective is included to discuss the challenges and potential opportunities for the interfacial engineering of Ti implants in a translational perspective. Overall, it is envisioned that the insights in this review may guide future research in the area of biometallic orthopedic implants for improving bone repair with enhanced efficacy and safety.

Intelligent luminescent materials for rewritable and programmable information display have long been expected to be used to address potential environmental concerns stemming from the extensive use of disposable displays. However, most reported luminescence-colour changeable examples are chemically responsive and not well programmed to sequentially deliver different information within a single system. Additionally, they may suffer from residual chemical accumulation caused by the repeated addition of chemical inks and usually have poor rewritability. Herein, we draw inspiration from the bioelectricity-triggered information display mechanism of chameleon skin to report a robust electrothermally powered polymer gel actuator consisting of one soft conductive graphene/PDMS film and one humidity-responsive fluorescence-colour changeable CD-functionalized polymer (PAHCDs) gel layer. Owing to the good electrocaloric effect of the bottom graphene film and excellent hygroscopicity of the top PAHCDs gel layer, the as-designed actuator could be facilely controlled to exhibit reversible and synergistic 3D-shape/fluorescence-colour changeable behaviours in response to alternating electricity and humidity stimuli. On this basis, robust rewritable information display systems are fabricated, which enable not only on-demand delivery of written information, but also facile rewriting of lots of different information by the synergization of electroheat/humidity-triggered local 3D-deformation and fluorescence-colour changes. This work opens new avenues of research into rewritable information display and potentially inspires the future development of intelligent luminescent materials.

Effective sequestration of bromine holds great promise for the chemical industry's safe expansion, environmental preservation, and public health. However, attaining this goal is still challenging due to the serious drawbacks of existing adsorbents such as limited capacity, low retention efficiency, and sluggish uptake kinetics. Herein, we report a strategy-driven systematic study aimed at significantly enhancing multiple host-guest interactions to obtain functionalized covalent-organic frameworks for the efficient sequestration of bromine. Results showed that the presence of specific quantities of selective binding sites of the porous frameworks afford stronger host-guest interactions and therefore higher bromine adsorption capacities. The developed framework exhibits high bromine sorption capacity of up to 5.16 g g^-1 in the vapor phase and 8.79 g g^-1 in the aqueous phase under static adsorption conditions with fast kinetics, large distribution coefficient (K_d ∼10⁵ mL g^-1), high retention efficiency and reusability. Moreover, the adsorbent is able to sequestrate trace bromine (from 13 ppm to below 4 ppm) from aqueous medium with fast adsorption kinetics (86.3% within less than 3 h) and demonstrates the selective extraction of bromine over iodine under both static and dynamic conditions. These results were further utilized to demonstrate recycling-selective and highly efficient bromine capture from a real-water system, exhibiting excellent scalability and affordability, as exemplified using COF membranes in a continuous flow-through process.

The generation of pseudo-magnetic fields in strained graphene leads to quantized Landau levels in the absence of an external magnetic field, providing the potential to achieve a zero-magnetic-field analogue of the quantum Hall effect. Here, we report the realization of a pseudo-magnetic field in epitaxial graphene by building a monolayer CrCl₂/graphene heterointerface. The CrCl₂ crystal structure exhibits spontaneous breaking of three-fold rotational symmetry, yielding an anisotropic displacement field at the interface. Using scanning tunneling spectroscopy, we have discovered a sequence of pseudo-Landau levels associated with massless Dirac fermions. A control experiment performed on the CrCl₂/NbSe₂ interface confirms the origin as the pseudo-magnetic field in the graphene layer that strongly interacts with CrCl₂. More interestingly, the strength of the pseudo-magnetic fields can be tuned by the twist angle between the monolayer CrCl₂ and graphene, with a variation of up to threefold, depending on the twist angle of 0° to 30°. This work presents a rare 2D heterojunction for exploring PMF-related physics, such as the valley Hall effect, with the advantage of easy and flexible implementation.