Materials Today Advances最新文献

Fabrication technologies based on electro-hydrodynamic processes have been extensively studied in the past decades. Near-field electrospinning (NFES), based on a stable cone-jet mode, is widely used to fabricate micro- and nano-scale fibrous structures for a variety of applications. However, previous reviews have given limited attention to the capabilities of NFES to fabricate 2D and 3D structures. This review introduces four key metrics of NFES capabilities, i.e., fidelity, resolution, response, and aspect ratio, to evaluate and summarize the advances of NFES technology. Specifically, the fundamental theories of the electro-hydrodynamic process are discussed to understand the effect of operating parameters on the metrics of NFES capabilities. Then, the methods to improve the metrics of NFES capabilities are summarized. Furthermore, the applications of NFES technology are reviewed by highlighting the functionality of each metric of the capabilities. Finally, the achievements and existing gaps in NFES technology are discussed to offer insights into future directions in the field.

Magnesium (Mg) alloys have great potential as biodegradable materials for medical device. However, their susceptibility to corrosion poses a significant challenge for practical applications. In this study, the poly(trimethylene carbonate)-dimethacrylate (PTMC-dMA) was employed as a coating material for ZE21B magnesium alloys. Upon UV irradiation, the PTMC-dMA macromer undergoes cross-linking to form a uniform PTMC coating with a thickness of approximately 5 μm, effectively protecting the magnesium alloy. The corrosion resistance in simulated body fluid (SBF) was evaluated through immersion testing, which showed minimal hydrogen generation (0.16 mL/cm²) during the initial 24-h period and slight corrosion observed on the PTMC-coated magnesium alloy surface after continuous immersion for 21 days. The silane coupling agent significantly enhanced the adhesive performance between the polymer and alloy. Micro-scratch tests revealed adhesion forces of 3.79 N and 5.75 N for coatings without and with the silane agent, respectively. Electrochemical tests also demonstrated the efficacy of silane treatment, showing corrosion currents of 2.100 × 10⁸ A/cm² for silane-treated samples compared 6.263 × 10⁷ A/cm² for untreated ones. Given its exceptional tensile and protective properties, this coated material is ideal for intricate bioresorbable applications, like endovascular bioresorbable stents.

Chronic diabetic cutaneous wounds resulting from inflammatory conditions present an ongoing challenge for current therapies and impose a significant burden on individuals with diabetes, impacting their quality of life. Infection-related diabetic skin wounds require dry conditions to inhibit bacterial growth. However, as the wounds progress, moisture becomes necessary to facilitate the healing process. In this study, we propose a novel therapeutic strategy for diabetic skin repair by creating bio-dressings with adjustable “hydrophobic” and “hydrophilic” characteristics to accommodate the changing stages of the disease. We developed a skin dressing by loading calcium peroxide (CaO₂) nanoparticles onto carbon dots (CD)-modified irradiated zein (Ir-Zein). This dressing releases reactive oxygen species (ROS) from CaO₂, providing antibacterial effects, while the presence of CD enables a sustained release of CaO₂. The calcium ions produced by CaO₂ degradation further promote skin regeneration. Ir-Zein protein, a cost-effective and easily processed natural plant protein, exhibits excellent biocompatibility. Importantly, in diabetic rats with full-thickness skin defects, the CaO₂/CD@Ir-Zein film significantly accelerated the healing of chronic wounds. Mechanistic investigations revealed that the film effectively reduced inflammation by inhibiting the polarization of macrophages towards the M1 phenotype and capturing pro-inflammatory cytokines. In summary, our findings demonstrate the effectiveness of the CaO₂/CD@Ir-Zein film’s “adaptive hydrophobicity-to-hydrophilicity” in promoting the transition of chronic wounds from the inflammatory stage and skin repair. CaO₂/CD@Ir Zein is a novel bio-dressing that can adapt to the changing environment of infected diabetic skin wound healing.

The precise structural design and reproducible manufacturing advantages of the 3D printed scaffold make it attract attention in clinical applications. However, the inability of scaffolds to achieve internal and external co-induced vascularized osteogenesis limits their application. After observing the ingenious and functionalized structural combination of "pinecone", this study prepared hydrogel microspheres encapsulating strontium ranelate (SrR)-dendrimer (PAMAM) as a functionalized "pine nuts" through microfluidic technology. The 3D-printed Polycaprolactone (PCL) scaffold was used as a framework in which hydrogel microspheres and a 3D-printed scaffold were cleverly combined. In this pinecone 3D-scaffold system, the slow release of SrR is beneficial to promote vascularization and osteogenic differentiation inside and outside the scaffold. Furthermore, the rat femoral defect model verified that the pinecone scaffold promoting the formation of internal vascular network, osteogenic differentiation and shortening the bone repair time in vivo. In summary, this pinecone degradable biomimetic composite scaffold with internal osteogenic differentiation and vascular activation functions has great potential for clinical demand in segmental bone defects.

Compared with conventional metallic glasses, refractory metallic glasses (RMGs) with a mass of refractory element(s), high glass-transition temperature (T_g) and outstanding mechanical properties (like ultrahigh strength, high hardness and good wear resistance) exhibit fascinating potential applications in high temperature field. However, the development of RMGs is painfully slow, and one of the key problems is the lack of rapid and convenient way to screen out high glass-forming refractory alloys. In this study, a method for rapid evaluation of glass forming ability (GFA) based on laser surface remelting was provided. The high-efficiency screening-out method was validated in a classical glass-forming model system of Ni–Nb binary refractory alloys. The effects of different laser parameters on the glass formation and phase evolution were investigated by experimental analysis and finite element simulation. By correlating thermal history of the laser treatment with glass formation, the alloys with high GFA in Ni–Nb system was screened out rapidly. The screening-out efficiency of the novel method can be improved one order of magnitude, compared with that of the conventional techniques, and the materials cost can be reduced, especially for RMGs. The revealed formation mechanism of glassy and crystalline phases in time and spatial distributions influenced by thermal history under multi-scanning laser treatment can provide a significant insight in the construction of the bulk-metallic-glass materials and the related composite ones by laser additive manufactory.

Electrochemically powered carbon nanotube (CNT) yarn muscles are of increasing interest because of their advantageous features as artificial muscles. They are light, and have high electrical properties, mechanical strength, and chemical stability. Twist-based CNT yarn muscles show superior actuation performance: 30 times the work capacity and 85 times the power density of natural muscles. Despite achieving these high performances, there is still potential for performance improvement because their twisted structure is not fully utilized. In particular, designing a cross-sectional structure that allows ions to freely enter and exit the twisted structure of the yarn muscle is necessary. Here, we propose highly enhanced artificial muscles with high chemical stability that consist of only nanocarbon materials of carbon nanoscroll (CNS) and twisted CNT yarns. The CNS/CNT yarn muscles (CCYM) can improve the ion accessibility and utilization of the twist structure. The maximum contractile stroke, work capacity, power density, and energy conversion efficiency of the CCYM were 20.11%, 2.26 J g⁻¹, 0.53 W g⁻¹, and 3.39%, which are 1.4-, 1.4-, 4.8, and 4.3 times that of the pristine CNT yarn muscles, respectively. The effects of CNS on CCYM were confirmed by experimental and theoretical analyses. Additionally, in a solid electrolyte, which opens up new application possibilities, the CCYM demonstrates high actuation performance (16.38%) with very low input energy.

TRistructural ISOtropic (TRISO) fuel is a leading-edge nuclear fuel form representing a departure from the more traditional nuclear fuel forms utilized in the reactor fleet of today. Rather than a monolithic fuel pellet of uranium dioxide, integral fuel forms containing TRISO fuel are composed of thousands of microencapsulated uranium-bearing fuel kernels and individually coated with multiple layers of pyrolytic carbon and silicon carbide. These multilayered ceramic coatings serve as an environmental barrier to ensure radioactive and chemically reactive fission products are contained within the reactor fuel elements, but also participate in the transfer of heat generated in the nuclear fuel to the coolant – the primary purpose of a nuclear reactor. Since traditional thermal property measurement techniques, such as laser flash analysis, would be unable to resolve the thermal properties of the individual TRISO coating layers, a simplified frequency-domain thermoreflectance technique has been developed to rapidly map the thermal properties of TRISO particles. Using this technique, the thermal properties of TRISO particles have been mapped from room temperature up to 1000 °C to examine the spatial variation and temperature-dependency of the thermal properties within each layer. Additionally, spatial-domain thermoreflectance was used to examine the anisotropy of the thermal properties for each layer at different locations within a single TRISO particle, and across multiple TRISO particles to assess the intra- and inter-particle uniformity of thermal properties, respectively. To elucidate the underlying causes for the measured variations in thermal properties, scanning electron microscopy and Raman spectroscopy were used to examine variations in microstructure and chemical bonding within the different coating layers. Results from this work are then compared with previous examinations of TRISO fuel particles and microstructurally driven mechanisms for the variations in the measured thermal properties of the different carbonaceous layers are discussed.

Compared with the wound in the flat part of human body, the repair of the wound in the joint, armpit and other frequently moving parts is still a complex problem. Although many flexible and adhesive hydrogel dressings for the repair of wounds at moving parts have been developed, in order to improve their flexibility and adhesion, most hydrogel dressings use synthetic polymers and natural polymers to form composite hydrogels, which greatly reduces their biocompatibility and bioactivity compared with a single natural polymer hydrogel. They can only passively provide a barrier to the wound and the process of wound repair is slow, which seriously hinders their further application. Inspired by commercial adhesive bandages, we have successfully constructed a flexible adhesive hydrogel dressing of embedded structure with pro-angiogenesis activity. The hydrogel was prepared by the adhesive and non-adhesive parts by topological adhesion and molecular entanglement. Due to the high-density hydrogen bonding, hydrogels possessed good adhesion and flexibility, which allowed them to repair wounds of moving parts successfully. In addition, the non-adhesive part loaded with exosomes was directly in contact with the wound, minimizing the stimulation of the wound tissue by cytotoxic materials, and continuously releasing active substances to promote vascular regeneration. This biocompatible flexible and adhesive hydrogel dressing with pro-angiogenesis activity shows strong potential in wound tissue remodeling, providing a new strategy for the treatment of moving parts or sensitive wound parts.

Two-dimensional (2D) metallic transition metal dichalcogenides (TMDs) have garnered significant attention as promising candidates for various applications, including electronics, spintronics, and energy-related fields. Their appeal lies in their exceptional electronic conductivity, room-temperature ferromagnetism, charge density wave (CDW) phenomena, and catalytic properties, among other attributes. Among the diverse array of metallic TMDs, vanadium dichalcogenides (VX₂, X = S, Se, and Te) stand out due to their distinctive set of physical and chemical properties. These properties have positioned VX₂ materials at the forefront of both fundamental research and technological exploration in fields such as condensed matter physics, materials science, and device physics. In this comprehensive review, we present a thorough investigation of the recent advancements in 2D metallic VX₂ materials and related heterostructures in the aspects of their structures, fabrication methods, key properties, and potential applications. First, the electronic and crystal structures of 2D VX₂ are introduced. Second, the growth methods of VX₂ and their heterostructures are discussed. Then, the novel physical properties and potential applications of 2D VX₂ and its heterostructures are highlighted. Finally, we assess the current state of development in this growing field, acknowledging the obstacles ahead and the promising avenues for future research.