Supramolecular coordination platinum metallacycle-based multilevel wound dressing for bacteria sensing and wound healing.

The exploitation of novel wound healing methods with real-time infection sensing and high spatiotemporal precision is highly important for human health. Pt-based metal-organic cycles/cages (MOCs) have been employed as multifunctional antibacterial agents due to their superior Pt-related therapeutic efficiency, various functional subunits and specific geometries. However, how to rationally apply these nanoscale MOCs on the macroscale with controllable therapeutic output is still challenging. Here, a centimeter-scale Pt MOC film was constructed via multistage assembly and subsequently coated on a N,N'-dimethylated dipyridinium thiazolo[5,4-d]thiazole (MPT)-stained silk fabric to form a smart wound dressing for bacterial sensing and wound healing. The MPT on silk fabric could be used to monitor wound infection in real-time through the bacteria-mediated reduction of MPT to its radical form via a color change. The MPT radical also exhibited an excellent photothermal effect under 660 nm light irradiation, which could not only be applied for photothermal therapy but also induce the disassembly of the Pt MOC film suprastructure. The highly ordered Pt MOC film suprastructure exhibited high biosafety, while it also showed improved antibacterial efficiency after thermally induced disassembly. In vitro and in vivo studies revealed that the combination of the Pt MOC film and MPT-stained silk can provide real-time information on wound infection for timely treatment through noninvasive techniques. This study paves the way for bacterial sensing and wound healing with centimeter-scale metal-organic materials.

By Introducing Multiple Hydrogen Bonds Endows MOF Electrodes with an Enhanced Structural Stability.

Recently, metal-organic frameworks (MOFs) have attracted great interest in energy storage areas. However, the poor structural stability of MOFs derived from weak coordination bonds limits their applications. Here, quadruple hydrogen bonds (H-bonds) were introduced onto the MOFs to enhance their structural stability. Cross-linked networks could be formed between molecules owing to multiple H-bonds, strengthening the framework stability. Moreover, the dynamic reversibility of H-bonds could endow MOFs with self-healing ability. Furthermore, due to lower binding energy compared to coordination bonds, H-bonds break preferentially when subjected to internal stress, thus protecting the MOFs. Consequently, the as-prepared self-healing hybrid (SHH-Cu-MOF@Ti3C2TX) exhibited high capacitance retention (89.4%) after 5000 cycles at 1 A g-1, while that hybrid without dynamic H-bonds (H-Cu-MOF@Ti3C2TX) presented a 79.9% retention, delivering an enhancement in cycling stability. Moreover, an asymmetric supercapacitor (ASC) was fabricated by employing SHH-Cu-MOF@Ti3C2TX and activated carbon (AC) as the electrodes. The ASC delivered a specific capacitance (47.4 F g-1 at 1 A g-1), an energy density (16.9 Wh kg-1), and a power density (800 W kg-1) as well as good rate ability (retains 81% of its initial capacitance from 0.2 A g-1 to 5 A g-1).

A Cascade-Reaction Nanoreactor Composed of a Bifunctional Molecularly Imprinted Polymer that Contains Pt Nanoparticles.

This study was aimed at addressing the present challenge of cascade reactions, namely, how to furnish the catalysts with desired and hierarchical catalytic ability. This issue was addressed by constructing a cascade-reaction nanoreactor made of a bifunctional molecularly imprinted polymer containing acidic catalytic sites and Pt nanoparticles. The acidic catalytic sites within the imprinted polymer allowed one specified reaction, whereas the encapsulated Pt nanoparticles were responsible for another coupled reaction. To that end, the unique imprinted polymer was fabricated by using two well-coupled templates, that is, 4-nitrophenyl acetate and 4-nitrophenol. The catalytic hydrolysis of the former compound at the acidic catalytic sites led to the formation of the latter compound, which was further reduced by the encapsulated Pt nanoparticles to 4-aminophenol. Therefore, this nanoreactor demonstrated a catalytic-cascade ability. This protocol opens up the opportunity to develop functional catalysts for complicated chemical processes.

An Overview of Recycling Phenolic Resin.

Over a century ago, phenolic formaldehyde (PF) resin was developed and continues to increase in yield due to its diverse applications. However, PF resin is a thermosetting plastic lacking fluidity and moldability, which are nondegradable in natural environments, leading to severe threats to fossil resources as well as global environmental crises. As a result, recycling PF resin is extremely important. In this review, we provide the recent advances in the recycling of PF resin, which includes mechanical recycling, chemical recycling, and utilization of carbon-based materials. The advantages and disadvantages of each strategy are evaluated from a green chemistry perspective. This article aims to attract interest in PF resin design, synthesizing, application and recycling, offering useful suggestions.

Progress and Challenges of Ferrite Matrix Microwave Absorption Materials.

Intelligent devices, when subjected to multiple interactions, tend to generate electromagnetic pollution, which can disrupt the normal functioning of electronic components. Ferrite, which acts as a microwave-absorbing material (MAM), offers a promising strategy to overcome this issue. To further enhance the microwave absorption properties of ferrite MAM, numerous works have been conducted, including ion doping and combining with other materials. Notably, the microstructure is also key factor that affects the microwave absorption properties of ferrite-based MAM. Thus, this article provides a comprehensive overview of research progress on the influence of the microstructure on ferrite-based MAM. MAMs with sheet and layered structures are also current important research directions. For core-shell structure composites, the solid core-shell structure, hollow core-shell structure, yolk-eggshell structure, and non-spherical core-shell structure are introduced. For porous composites, the biomass porous structure and other porous structures are presented. Finally, the development trends are summarized, and prospects for the structure design and preparation of high-performance MAMs are predicted.

Progress and challenges of emerging MXene based materials for thermoelectric applications.

To realize sustainable development, more and more countries forwarded carbon neutrality goal. Accordingly, improving the utilization efficiency of traditional fossil fuel is an effective strategy for this great goal. Keeping this in mind, developing thermoelectric devices to recover waste heat energy resulted in the consumption process of fuel is demonstrated to be promising. High performance thermoelectric devices require advanced materials. MXenes are a kind of 2D materials with a layered structure, which demonstrate excellent thermoelectric performance owing to their unique physical, mechanical, and chemical properties. Also, substantial achievement has been gained during the past few years in synthesizing MXene based materials for thermoelectric devices. In this review, the mainstream synthetic routes of MXene from etching MAX were summarized. Significantly, the current state and challenges of research on improving the performance of MXene based thermoelectrics are explored, including pristine MXene and MXene based composites.

Zn-BTC MOF as Self-Template to Hierarchical ZnS/NiS2 Heterostructure with Improved Electrochemical Performance for Hybrid Supercapacitor.

Zn-BTC (H3BTC refers to 1, 3, 5-benzoic acid) MOF was used as a self-template and a zinc source to prepare ZnS/NiS2 with a layered heterogeneous structure as a promising electrode material using cation exchange and solid-phase vulcanization processes. The synergistic effect of the two metal sulfides enhances the application of ZnS/NiS2. And the high specific surface area and abundant active sites further promote the mass/charge transfer and redox reaction kinetics. In the three-electrode system, the specific capacitance was as high as 1547 F/g at a current density of 1 A/g, along with satisfactory rate capability (1214 F/g at 6 A/g) and cycling performance. Coupled with activated carbon (AC), the prepared hybrid device (ZnS/NiS2 as the positive electrode and AC as the negative electrode) (ZnS/NiS2/AC) can be operated under a potential window of 1.6 V and provides a high energy density of 26.3 Wh/kg at a power density of 794 W/kg. Notably, the assembled ZnS/NiS2//AC showed little capacity degradation after 5000 charge/discharge cycles.

An enzyme-like imprinted-polymer reactor with segregated quantum confinements for a tandem catalyst.

This study was aimed at addressing the present challenge in tandem catalysts, as to how to furnish catalysts with tandem catalytic-ability without involving the precise control and man-made isolation of different types of catalytic sites. This objective was realized by constructing an enzyme-like imprinted-polymer reactor made of a unique polymer composite inspired from the compartmentalization of cells, a composite of a reactive imprinted polymer (containing acidic catalytic sites), and encapsulated metal nanoparticles (acting as catalytic reduction sites). The compilation of two types of catalytic sites with admissible access allowed this reactor to behave like compartments of cells for enzymatic reactions and hence catalytically constituted two quantum interaction-segregated domains, which led to the occurrence of catalytic tandem processes. Unlike the reported functional reactors that run tandem catalysis by largely depending on the precise control and man-made isolation of different types of catalytic sites, tandem catalysis in this reactor run naturally with segregated quantum confinements, which does not involve the precise control and isolation of different types of catalytic sites. This protocol presents new opportunities for the development of functional catalysts for complicated chemical processes.

Antimicrobial and antioxidant capacity of glucosamine-zinc(II) complex via non-enzymatic browning reaction.

Coordination compounds play an important role in the life process, and have been widely used in food, cosmetics and pharmaceutical industry. Herein, we have developed a novel kind of glucosamine-zinc(II) complex (GlcN-ZC) for food additive using non-enzymatic browning reaction. The GlcN-ZC was characterized by FTIR and XRD. Moreover, UV absorbance changes, browning intensity, fluorescence changes, antioxidant activity and antimicrobial assessment of GlcN-ZC were also evaluated. Results showed the GlcN-ZC intermediate compounds were accumulated in non-enzymatic browning while prolonging heating time and melanoidins were produced in the final stage. The fluorescence changes confirmed that fluorophores were formed during the non-enzymatic reaction and fluorescence intensity reached a maximun at 60 min. The highest radical scavenging activity of GlcN-ZC formed after 180 min of heating was 79.2%. Furthermore, GlcN-ZC exhibited excellent antibacterial activity against E. coli and S. aureus. Therefore, GlcN-ZC can be used as a novel promising additive in the food industry.

Facile fabrication of hierarchically porous CuFe2O4 nanospheres with enhanced capacitance property.

In this work, CuFe2O4 nanospheres with hierarchically porous structure have been synthesized via a facile solvothermal procedure. The superstructures consist of the textured aggregations of nanocrystals with high specific surface area, pore volume, and uniform pore size distribution.To figure out the formation mechanism, we discussed in detail the effects of a series of experimental parameters, including the concentrations of the precipitation agent, stabilizer agent, and reaction temperature and time on the size and morphology of the resulting products. Furthermore, the electrochemical properties of CuFe2O4 nanospheres were evaluated by cyclic voltammetry and galvanostatic charge-dischrge studies. The results demonstrate that the as-prepared CuFe2O4 nanospheres are excellent electrode material in supercapacitor with high specific capacitance and good retention. The hierarchically CuFe2O4 nanospheres show the highest capacitance of 334F/g, and 88% of which can still be maintained after 600 charge-discharge cycles.

Review on the progress in synthesis and application of magnetic carbon nanocomposites.

This review focuses on the synthesis and application of nanostructured composites containing magnetic nanostructures and carbon-based materials. Great progress in fabrication of magnetic carbon nanocomposites has been made by developing methods including filling process, template-based synthesis, chemical vapor deposition, hydrothermal/solvothermal method, pyrolysis procedure, sol-gel process, detonation induced reaction, self-assembly method, etc. The applications of magnetic carbon nanocomposites expanded to a wide range of fields such as environmental treatment, microwave absorption, magnetic recording media, electrochemical sensor, catalysis, separation/recognization of biomolecules and drug delivery are discussed. Finally, some future trends and perspectives in this research area are outlined.