Frontiers of Materials Science最新文献

Microorganisms coexist with human beings and have formed a complex relationship with us. However, the abnormal spread of pathogens can cause infectious diseases thus demands antibacterial agents. Currently available antimicrobials, such as silver ions, antimicrobial peptides and antibiotics, have diverse concerns in chemical stability, biocompatibility, or triggering drug resistance. The “encapsulate-and-deliver” strategy can protect antimicrobials against decomposing, so to avoid large dose release induced resistance and achieve the controlled release. Considering loading capacity, engineering feasibility, and economic viability, inorganic hollow mesoporous spheres (iHMSs) represent one kind of promising and suitable candidates for real-life antimicrobial applications. Here we reviewed the recent research progress of iHMSs-based antimicrobial delivery. We summarized the synthesis of iHMSs and the drug loading method of various antimicrobials, and discussed the future applications. To prevent and mitigate the spread of an infective disease, multilateral coordination at the national level is required. Moreover, developing effective and practicable antimicrobials is the key to enhancing our capability to eliminate pathogenic microbes. We believe that our conclusion will be beneficial for researches on the antimicrobial delivery in both lab and mass production phases.

A hydrophilic hyperbranched polyester (poly (tetramethylol acetylenediurea (TA)-CO-succinyl chloride) (PTS)) was proposed to be used as an organic additive in aqueous ZnSO₄ electrolyte to achieve a highly reversible zinc/manganese oxide battery. It is found that the zinc symmetric battery based on the 2.0 wt.% PTS/ZnSO₄ electrolyte showed a long cycle stability of more than 2400 h at 1.0 mA·cm⁻², which is much longer than that including the blank ZnSO₄ electrolyte (140 h). Furthermore, the capacity retention of the Zn||MnO₂ full cells employing the 2.0 wt.% PTS/ZnSO₄ electrolyte remained 85% after 100 cycles at 0.2 A·g⁻¹, which is much higher than 20% capacity retention of the cell containing the blank ZnSO₄ electrolyte, and also greater than 59.6% capacity retention of the cell including the 10.0 wt.% TA/ZnSO₄ electrolyte. By using 2.0 wt.% PTS/ZnSO4 electrolytes, the capacity retention of the Zn||MnO2 full cells even reached 65% after 2000 cycles at a higher current density of 1.0 A·g⁻¹. It is further demonstrated that the PTS was firmly adsorbed on the zinc anode surface to form a protective layer.

Titanium and its alloys are often used as substrates for dental implants due to their excellent mechanical properties and good biocompatibility. However, their ability to bind to neighboring bone is limited due to the lack of biological activity. At the same time, they show poor antibacterial ability which can easily cause bacterial infection and chronic inflammation, eventually resulting in implant failure. The preparation of composite hydroxyapatite coatings with antibacterial ability can effectively figure out these concerns. In this review, the research status and development trends of antibacterial hydroxyapatite coatings constructed on titanium and its alloys are analyzed and reviewed. This review may provide valuable reference for the preparation and application of high-performance and multi-functional dental implant coatings in the future.

Recently, alcohols have attracted more attention due to their excellent tribological performance, especially superlubricity under low loads. Alcohol solution, as a liquid lubricant, can easily reach the superlubricity state under low loads because of the formed low shear hydroxylation interfaces induced by the tribochemical reactions. A general picture and its influencing factors have been elucidated, not only at the macroscopic scale but also at the nanoscale, which is sufficient to provide effective guidance for lubrication design and tribology research in engineering. Herein, we provide a review on the recent applications of alcohols in lubrication. In addition, the material transformation caused by alcohols in friction is a key factor affecting the tribological properties. As an important two-dimensional material, the growth mechanisms of graphene are variable, and the most famous is the formation of carbon radicals under the action of metal catalysts. Thus, based on the formation mechanism of carbon friction film (such as amorphous carbon and graphene), the main content of this review also includes the transformation of graphene in alcohol solution friction process.

Fe₃O₄ nanoparticles (NPs) are widely used in the construction of drug and gene delivery vectors because of their particular physicochemical properties. Surface modification can not only reduce the cytotoxicity of Fe₃O₄, but also further improve the biocompatibility and delivery efficiency. In this work, firstly, polydopamine (PDA)-coated Fe₃O₄ NPs (named Fe₃O₄@PDA) were prepared by using the self-polymerization characteristics of dopamine in alkaline environment. Then, polyamidoamine (PAMAM) was modified by the Michael addition reaction to prepare water-soluble core—shell magnetic NPs of Fe₃O₄@PDA@PAMAM, and its potential as gene vector was further evaluated. The results revealed that Fe₃O₄@PDA@PAMAM had the ability to condense and protect DNA, and showed lower cytotoxicity, higher cell uptake and transfection efficiency than those of PAMAM. It has the potential to become a magnetic targeted gene vector for further study.

As a novel energy-harvesting device, a triboelectric nanogenerator (TENG) can harvest almost all mechanical energy and transform it into electrical energy, but its output is low. Although the micro-nano structures of triboelectrode surfaces can improve their output efficiency, they lead to high costs and are not suitable for large-scale applications. To address this problem, we developed a novel TENG coating with charge-storage properties. In this study, we modified an acrylic resin, a friction material, with nano-BaTiO₃ particles and gas phase fluorination. The charge-trapping ability of nanoparticles was used to improve the output of TENG. The short-circuit current and the output voltage of coating-based TENGs featuring charge storage and electrification reached 15 µA and 800 V, respectively, without decay for longtime working. On this basis, self-powered anticorrosion and antifouling systems are designed to reduce the open circuit potential of A3 steel by 510 mV and reduce the adhesion rate of algae on the surface of metal materials. This study presents a high-output, stable, coating-based TENG with potential in practical applications for anticorrosion and antifouling.

A unique family of renewable polymers has been constructed through facile chemical and physical approaches. In viewing of the abundant and renewable characteristics of starch, cellulose, chitosan and alginate, they are adopted as starting materials. Lactic acid and carbon dioxide, which can be regarded as derivates of starch, are also adopted as starting materials since both of them are abundant, non-toxic and renewable. For sake of making the intension to be carried out easily, the applied chemical or physical approaches are as facile as possible. After two decades of effort, a variety of polymers with versatile properties such as improved mechanical strength, good adsorption or loading capacity and various intelligent behaviors have been tailor-made. These polymers are designed systematically instead of obtaining at random. Herein, our ideas and the strategies for developing the polysaccharide-based renewable polymers are elucidated. It is expected that what presented in this article could stimulate more ideas to develop renewable polymers and bring brighter prospect of the polysaccharide-family.

The Golgi apparatus is one of the important organelles, where the final processing and packaging of cellular secretions (such as proteins) are completed. The disorder of Golgi apparatus structure and function will induce many diseases. Therefore, monitoring the morphological structure of Golgi apparatus is crucial for the diagnosis and treatment of relevant diseases. In order to achieve Golgi apparatus-targeting imaging, the strategy of targeting unit inheritance was adopted and carbon dots (CDs) with Golgi apparatus-targeting ability were synthesized by one-step hydrothermal method with L-ascorbic acid with high reactivity and reducibility as the carbon source and L-cysteine as the targeting unit. CDs have a certain amount of cysteine residues on their surface, and have excitation dependence, satisfactory fluorescence and cysteine residues stability and low toxicity. As an imaging agent, CDs can be used for targeting imaging of Golgi apparatus.

Tungsten (W) has become the most promising plasma-facing material (PFM) in fusion reactor, and W still faces performance degradation caused by low-temperature brittleness, low recrystallization temperature, neutron irradiation effects, and plasma irradiation effects. The modification of W/W-based materials in terms of microstructure manipulation is needed, and such techniques to improve the performance of materials are the topics of hot research. Researchers have found that refining the grain can significantly improve the strength and the irradiation resistance of W/W-based materials. In this paper, novel approaches and technique routes, including the “bottom-up” powder metallurgy method and “top-down” severe plastic deformation method, are introduced to the fabrication of nanocrystalline W/W-based materials. The formation mechanisms of nanocrystalline W/W-based materials were revealed, and the nanostructure stabilization mechanisms were introduced. The mechanical properties of nanocrystalline W/W-based materials were tested, and the irradiation behaviors and performances were studied. The mechanisms of their high mechanical properties and excellent irradiation-damage resistance were illustrated. This article may provide an experimental and theoretical basis for the design and development of high-performance novel nanocrystalline W/W-based materials.

Lithium-sulfur (Li−S) battery has been considered as one of the most promising future batteries owing to the high theoretical energy density (2600 W·h·kg⁻¹) and the usage of the inexpensive active materials (elemental sulfur). The recent progress in fundamental research and engineering of the Li−S battery, involved in electrode, electrolyte, membrane, binder, and current collector, has greatly promoted the performance of Li−S batteries from the laboratory level to the approaching practical level. However, the safety concerns still deserve attention in the following application stage. This review focuses on the development of the electrolyte for Li−S batteries from liquid state to solid state. Some problems and the corresponding solutions are emphasized, such as the soluble lithium polysulfides migration, ionic conductivity of electrolyte, the interface contact between electrolyte and electrode, and the reaction kinetics. Moreover, future perspectives of the safe and high-performance Li−S batteries are also introduced.