Frontiers of Materials Science最新文献

Microbe-related, especially viral-related pandemics have currently paralyzed the world and such pathogenesis is expected to rise in the upcoming years. Although tremendous efforts are being made to develop antiviral drugs, very limited progress has been made in this direction. The nanotheranostic approach can be a highly potential rescue to combat this pandemic. Nanoparticles (NPs) due to their high specificity and biofunctionalization ability could be utilized efficiently for prophylaxis, diagnosis and treatment against microbial infections. In this context, titanium oxide, silver, gold NPs, etc. have already been utilized against deadly viruses like influenza, Ebola, HIV, and HBV. The discovery of sophisticated nanovaccines is under investigation and of prime importance to induce reproducible and strong immune responses against difficult pathogens. This review focuses on highlighting the role of various nano-domain materials such as metallic NPs, magnetic NPs, and quantum dots in the biomedical applications to combat the deadly microbial infections. Further, it also discusses the nanovaccines those are already available for various microbial diseases or are in clinical trials. Finally, it gives a perspective on the various nanotechnologies presently employed for efficient diagnosis and therapy against disease causing microbial infections, and how advancement in this field can benefit the health sector remarkably.

Non-noble metal electrocatalysts for water cracking have excellent prospects for development of sustainable and clean energy. Highly efficient electrocatalysts for the oxygen evolution reaction (OER) are very important for various energy storage and conversion systems such as water splitting devices and metal-air batteries. This study prepared a NiMo₄@C₃N₄ catalyst for OER and hydrogen evolution reaction (HER) by simple methods. The catalyst exhibited an excellent OER activity based on the response at a suitable temperature. To drive a current density of 10 mA·cm⁻² for OER and HER, the overpotentials required for NiMo₄@C₃N₄-800 (prepared at 800 °C) were 259 and 118 mV, respectively. A two-electrode system using NiMo₄@C₃N₄-800 needed a very low cell potential of 1.572 V to reach a current density of 10 mA·cm⁻². In addition, this catalyst showed excellent durability after long-term tests. It was seen to have good catalytic activity and broad application prospects.

The SnO₂-based family is a traditional but important gas-sensitive material. However, the requirement for high working temperature limits its practical application. Much work has been done to explore ways to improve its gas-sensing performance at room temperature (RT). For this report, SnO₂, SnO, and SnO/SnO₂ heterojunction was successfully synthesized by a facile hydrothermal combined with subsequent calcination. Pure SnO₂ requires a high operating temperature (145 °C), while SnO/SnO₂ heterojunction exhibits an excellent performance for sensing NO₂ at RT. Moreover, SnO/SnO₂ exhibits a fast response, of 32 s, to 50 ppm NO₂ at RT (27 °C), which is much faster than that of SnO (139 s). The superior sensing properties of SnO/SnO₂ heterojunction are attributed to the unique hierarchical structures, large number of adsorption sites, and enhanced electron transport. Our results show that SnO/SnO₂ heterojunction can be used as a promising high-performance NO₂ sensitive material at RT.

The low surface area, high recombination rate of photogenerated charge carriers, narrow visible range activity, and difficulty in the separation from cleaned solutions limit the wide application of g-C₃N₄ as a photocatalyst. Herein, we have succeeded in developing a one-pot strategy to overcome the above-mentioned difficulties of g-C₃N₄. The broadening of the visible-light response range and inducing magnetic nature to g-C₃N₄ was succeeded by preparing a nanocomposite with Fe₂O₃ via a facile solvothermal method. The preparation method additionally imparted layer exfoliation of g-C₃N₄ as evident from the XRD patterns and TEM images. The strong interaction between the components is revealed from the XPS analysis. The broadened visible-light absorbance of Fe₂O₃/g-C₃N₄ with a Z-scheme photocatalytic degradation mechanism is well evident from the UV—Vis DRS analysis and PL measurement of the composite with terephthalic acid. The active species of photocatalysis were further investigated using scavenging studies in methylene blue degradation that revealed hydroxyl radicals and holes as the major contributors to the activity of Fe₂O₃/g-C₃N₄.

Electroactive hydrogels could guide the regeneration of nerves and promote their functional recovery. An aniline pentamer-crosslinked chitosan (CS-AP) hydrogel with better electroactivity and degradation was fabricated by the carbodiimide method, and then injected into the repair site of sciatic nerve damage, with its gelation time, tensile strength, and conductivity reaching 35 min, 5.02–6.69 MPa, and from 2.97 × 10⁻⁴ to 3.25 × 10⁻⁴ S·cm⁻¹, respectively, due to the cross-linkage and well-distribution of AP. There was better cytocompativility of CS-AP hydrogel on nerve cells. The results of the in vivo repair indicated that CS-AP10 hydrogel induced the capillaries formation and the repair of sciatic nerve defect, and re-innervated gastrocnemius muscle in the CS-AP10 group were obviously better than other experimental groups, due to the electroactivity of CS-AP and its degradation into fragments. These results indicated the potential application of CS-AP hydrogel in the regeneration and function recovery of peripheral nerve injury.

During this decade, graphene which is a thin layer of carbon material along at ease with synthesis and functionalization has become a hot topic of research owing to excellent mechanical strength, very good current density, high thermal conductivity, superior electrical conductivity, large surface area, and good electron mobility. The research on graphene has exponentially accelerated specially when Geim and Novoselov developed and analyzed graphene. On this basis, for industrial application, researchers are exploring different techniques to produce high-quality graphene. Therefore, reviewed in this article is a brief introduction to graphene and its derivatives along with some of the methods developed to synthesize graphene and its prospective applications in both research and industry. In this work, recent advances on applications of graphene in various fields such as sensors, energy storage, energy harvesting, high-speed optoelectronics, supercapacitors, touch-based flexible screens, and organic light emitting diode displays have been summarized.

As an anode material for sodium-ion batteries (SIBs), bismuth (Bi) has attracted widespread attention due to its suitable voltage platform and high volumetric energy density. However, the severe volume expansion of Bi during charging and discharging leads to a rapid decline in battery capacity. Loading Bi on the graphene can relieve volume expansion and improve electrochemical performance. However, excessive loading of Bi on graphene will cause the porosity of the composite material to decrease, which leads to a decrease of the Na⁺ transmission rate. Herein, the Bi/three-dimensional porous graphene (Bi/3DPG) composite material was prepared and the pore structure was optimized to obtain the medium-load Bi/3DPG (Bi/3DPG-M) with better electrochemical performance. Bi/3DPG-M exhibited a fast kinetic process while maintaining a high specific capacity. The specific capacity still remained at 270 mA·h·g⁻¹ (93.3%) after 500 cycles at a current density of 0.1 A·g⁻¹. Even at 5 A·g⁻¹, the specific capacity of Bi/3DPG-M could still reach 266.1 mA·h·g⁻¹. This work can provide a reference for research on the use of alloy—graphene composite in the anode of SIBs.

Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug delivery. Herein, novel hollow bioactive glass nanospheres (HBGn) with large hollow cavity and large mesopores in their outer shells were synthesized by a simple and facile one-pot ultrasound assisted sol—gel method using PEG as the core soft-template. Interestingly, the produced HBGn exhibited large hollow cavity with ∼43 nm in diameter and mesoporous shell of ∼37 nm in thickness and 7 nm pore size along with nanosphere size around 117 nm. XPS confirmed the presence of Si and Ca elements at the surface of the HBGn outer shell. Notably, HBGn showed high protein loading capacity (∼570 mg of Cyto c per 1 g of HBGn) in addition to controlled protein release over 5 d. HBGn also demonstrated a good in vitro capability of releasing calcium (Ca²⁺: 170 ppm) and silicate (SiO₄⁴⁻: 78 ppm) ions in an aqueous medium over 2 weeks under physiological-like conditions. Excellent in vitro growth of bone-like hydroxyapatite nanocrystals was exhibited by HBGn during the soaking in SBF. A possible underlying mechanism involving the formation of spherical aggregates (coils) of PEG was proposed for the formation process of HBGn.

Metal oxides are considered as potential anodes for sodium-ion batteries (SIBs). Nevertheless, they suffer from poor cycling and rate capability. Here, we investigate conductive polymer coating on Co₃O₄ nanoparticles varying with different percentages. X-ray diffraction, electron microscopy and surface chemical analysis were adopted to analyze coated and uncoated Co₃O₄ nanoparticles. Conducting polymer, poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS), has been utilized for coating. Improved specific capacity and rate capability for an optimal coating of 0.5 wt.% were observed. The 0.5 wt.% coated sample outperformed the uncoated one in terms of capacity, rate capability and coulombic efficiency. It delivered a reversible capacity of 561 mAh·g⁻¹ at 100 mA·g⁻¹ and maintained a capacity of 318 mAh·g⁻¹ at a high rate of 1 A·g⁻¹. Increasing the PEDOT:PSS coating percentage led to lower performance due to the thicker coating induced kinetic issues. Ex-situ analysis of the 0.5 wt.% coated sample after 100 cycles at 1 A·g⁻¹ was characterized for performance correlation. Such a simple, cost-effective and wet-chemical approach has not been employed before for Co₃O₄ as the SIB anode.

Smart drug delivery nanocarriers with high drug loading capacity are of great importance in the treatment of diseases, and can improve therapeutic effectiveness as well as alleviate side effects in patients. In this work, a pH and H₂O₂-responsive drug delivery platform with high doxorubicin (DOX) loading capacity has been established through coordination interaction between DOX and phenylboronic acid containing block polymer. A composited drug nanocarrier is further fabricated by growing a zeolitic imidazolate framework 8 (ZIF-8) on the surface of drug-loaded polymer micelles. The study verifies that ZIF-8 shell can act as intelligent “switch” to prevent DOX leaking from core-shell nanoparticles upon H₂O₂ stimulus. However, a burst drug release is detected upon pH and H₂O₂ stimuli due to the further disassociation of ZIF-8 in acid solution. Moreover, the in vitro anti-cancer experiments demonstrate that the DOX-loaded core—shell nanoparticles provide effective treatment towards cancer cells but have negligible effect on normal cells, which results from the high concentration of H₂O₂ and low pH in the microenvironment of tumor cells.