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Persistent inflammation and bacterial infection commonly occur during the wound healing process, necessitating urgent development of effective strategies for treating drug-resistant bacterial infections. In this study, bismuth vanadate (BiVO 4 ) was successfully synthesized as an antibacterial agent that promotes wound healing. Through In vitro antibacterial experiments, it was observed that the prepared BiVO 4 exhibited excellent performance in catalyzing H 2 O 2 to produce hydroxyl radicals (OH) at a lower concentration (0.2 mg mL -1 ), resulting in significant antibacterial effects against Gram-negative Extended-Spectrum β-Lactamases-Producing Escherichia coli (ESBL-E. coli) strains. Furthermore, biosafety tests, cell scratch experiments, and ESBL-E. coli infected wound rat model experiments demonstrated high biocompatibility of BiVO 4 with a cell survival rate exceeding 85 %. Additionally, BiVO 4 promoted the production of vascular endothelial growth factors and fibroblasts migration while contributing to collagen production, effectively facilitating immune reconstruction at the wound site. By integrating peroxidase (POD)-like under acidic conditions (pH 4) and catalase (CAT)-like catalytic activities at under neutral conditions (pH 7), BiVO 4 exhibited the ability to activate free radical sterilization and accelerate wound healing by activating O 2 . Therefore, our findings provide evidence for a dual enzyme regulatory mechanism involving antibacterial properties and promotion of wound tissue reconstruction for potential application in both antibacterial treatment and wound healing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The use of traditional Ag-based antibacterial agents is usually accompanied by uncontrollable silver release, which makes it difficult to find a balance between antibacterial performance and biosafety. Herein, we prepared a core-shell system of ZIF-8-derived amorphous carbon-coated Ag nanoparticles (Ag@C) as an ideal research model to reveal the synergistic effect and structure-activity relationship of the structural transformation of carbon shell and Ag core on the regulation of silver release behavior. It is found that Ag@C prepared at 600 °C (AC6) exhibits the best ion release kinetics due to the combination of relatively simple shell structure and lower crystallinity of the Ag core, thereby exerting stronger antibacterial properties (>99.999 %) at trace doses (20 μg mL -1 ) compared with most other Ag-based materials. Meanwhile, the carbon shell prevents the metal Ag from being directly exposed to the organism and thus endows AC6 with excellent biocompatibility. In animal experiments, AC6 can effectively promote wound healing by inactivating drug-resistant bacteria while regulating the expression of TNF-α and CD31. This work provides theoretical support for the scientific design and clinical application of controllable ion-releasing antibacterial agents., (© 2024 Wiley-VCH GmbH.)

Salinity is considered one of the abiotic stresses that have the greatest impact on soybean production worldwide. Lanthanum (La) is a rare earth element that can reduce adverse conditions on plant growth and productivity. However, the regulatory mechanism of La-mediated plant response to salt stress has been poorly studied, particularly in soybeans. Therefore, our study investigated the mechanisms of La-mediated salt stress alleviation from the perspectives of the antioxidant system, subcellular structure, and metabolomics responses. The results indicated that salt stress altered plant morphology and biomass, resulting in an increase in peroxidation, inhibition of photosynthesis, and damage to leaf structure. Exogenous La application effectively promoted the activity of superoxide dismutase (SOD) and peroxidase (POD), as well as the soluble protein content, while decreasing the Na + content and Na + /K + ratio in roots and leaves, and reducing oxidative damage. Moreover, transmission electron microscopy (TEM) demonstrated that La prevented the disintegration of chloroplasts. Fourier-transform infrared spectroscopy (FTIR) analysis further confirmed that La addition mitigated the decline in protein, carbohydrates, and pectin levels in the leaves. Lanthanum decreased the leaf flavonoid content and synthesis by inhibiting the content of key substances in the phenylalanine metabolism pathway during NaCl exposure. Collectively, our research indicates that La reduces cell damage by regulating the antioxidant system and secondary metabolite synthesis, which are important mechanisms for the adaptive response of soybean leaves, thereby improving the salt tolerance of soybeans., (© 2024 Scandinavian Plant Physiology Society.)

Soil salinization is a major abiotic factor threatening rapeseed yields and quality worldwide, yet the adaptive mechanisms underlying salt resistance in rapeseed are not clear. Therefore, this study aimed to explore the differences in growth potential, sodium (Na + ) retention in different plant tissues, and transport patterns between salt-tolerant (HY9) and salt-sensitive (XY15) rapeseed genotypes, which cultivated in Hoagland's nutrient solution in either the with or without of 150 mM NaCl stress. The results showed that the inhibition of growth-related parameters of the XY15 genotype was higher than those of the HY9 in response to salt stress. The XY15 had lower photosynthesis, chloroplast disintegration, and pigment content but higher oxidative damage than the HY9. Under NaCl treatment, the proline content in the root of HY9 variety increased by 8.47-fold, surpassing XY15 (5.41-fold). Under salt stress, the HY9 maintained lower Na + content, while higher K + content and exhibited a relatively abundant K + /Na + ratio in root and leaf. HY9 also had lower Na + absorption, Na + concentration in xylem sap, and Na + transfer factor than XY15. Moreover, more Na + contents were accumulated in the root cell wall of HY9 with higher pectin content and pectin methylesterase (PME) activity than XY15. Collectively, our results showed that salt-tolerant varieties absorbed lower Na + and retained more Na + in the root cell wall (carboxyl group in pectin) to avoid leaf salt toxicity and induced higher proline accumulation as a defense and antioxidant system, resulting in higher resistance to salt stress, which provides the theoretical basis for screening salt resistant cultivars., (© 2024 Scandinavian Plant Physiology Society.)

Static repellency and pressure resistance to liquids are essential for high-performance super-omniphobic surfaces. However, these two merits appear mutually exclusive in conventional designs because of their conflicting structural demands: Static liquid repellency necessitates minimal solid-liquid contact, which in turn inevitably undercuts the surface's ability to resist liquid invasion exerted by the elevated pressure. Here, inspired by the Springtail, these two merits can be simultaneously realized by structuring surfaces at two size scales, with a micrometric reentrant structure providing static liquid repellency and a nanometric reentrant structure providing pressure resistance, which dexterously avoids the dilemma of their structural conflicts. The nanometric reentrants are densely packed on the micrometric ones, serving as "armor" that prevents liquids invasion by generating multilevel energy barriers, thus naming the surface as the armored reentrants (AR) surface. The AR surface could repel liquids with very low surface tensions, such as silicone oil (21 mN m -1 ), and simultaneously resist great pressure from the liquids, exemplified by enduring the impact of low-surface-tension liquids under a high weber number (>400), the highest-pressure resistance ever reported. With its scalable fabrication and enhanced performance, our design could extend the application scope of liquid-repellent surfaces toward ultimate industrial settings., (© 2023 Wiley‐VCH GmbH.)

Soil salinization has become a global problem that threatens farmland health and restricts crop production. Salt-affected soils seriously restrict the development of agricultural, mainly because of sodium ion (Na + ) toxicity, nutrient deficiency, and structural changes in the soil. Biochar is a carbon (C)-based substance produced by heating typical biomass waste at high temperatures in anaerobic circumstances. It has high cation exchange capacity (CEC), adsorption capacity, and C content, which is often used as a soil amendment. Biochar generally reduces the concentration of Na + in soil colloids through its strong adsorption, or uses the calcium (Ca) or magnesium (Mg) rich on its surface to exchange sodium ions (Ex-Na) from soil colloids through cation exchange to accelerate salt leaching during irrigation. Nowadays, biochar is widely used for acidic soils improvement due to its alkaline properties. Although the fact that biochar has gained increasing attention for its significant role in saline alkali soil remediation, there is currently a lack of systematic research on biochar improvers and their potential mechanisms for identifying physical, chemical, and biological indicators of soil eco-environment assessment and plant growth conditions affected by salt stress. This paper reviews the preparation, modification, and activation of biochar, the effects of biochar and its combination with beneficial salt-tolerant strains on salt-affected soils and plant growth. Finally, the limitations, benefits, and future needs of biochar-based soil health assessment technology in salt-affected soils and plant were discussed. This article elaborates on the future opportunities and challenges of biochar in the treatment of saline land, and a green method was provided for the integrate control to salt-affected soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Fenton reactions are inefficient because the Fe(II) catalyst cannot be recycled in time due to the lack of a rapid electron transport pathway. This results in huge H 2 O 2 wastage in industrial applications. Here, it is shown that a sustainable heterogeneous Fenton system is attainable by enhancing the ligand-to-metal charge-transfer (LMCT) excited-state lifetime in Fe-gallate complex. By engineering oxygen defects in the complex, the lifetime is improved from 10-90 ps. The lengthened lifetime ensures sufficient concentrations of excited-states for an efficient Fe cycle, realizing previously unattainable H 2 O 2 activation kinetics and hydroxyl radical ( • OH) productivity. Spectroscopic and electrochemical studies show the cyclic reaction mechanism involves in situ Fe(II) regeneration and synchronous supply of oxygen atoms from water to recover dissociated Fe─O bonds. Trace amounts of this catalyst effectively destroy two drug-resistant bacteria even after eight reaction cycles. This work reveals the link among LMCT excited-state lifetime, Fe cycle, and catalytic activity and stability, with implications for de novo design of efficient and sustainable Fenton-like processes., (© 2023 Wiley-VCH GmbH.)

Xanthine-functionalized molybdenum oxide nanodots (X-MoO 3-x NDs) with peroxidase (POD)-like activity were developed for selective, sensitive, and facile colorimetric quantification of xanthine oxidase (XO). Xanthine functionalization can not only be favorable for the successful nanozyme preparation, but also for the specific recognition of XO as well as the simultaneous generation of hydrogen peroxide, which was subsequently transformed into hydroxyl radical to oxidize the chromogenic reagent based on the POD-like catalysis. Under the optimized conditions, the colorimetric biosensing platform was established for XO assay without addition of further substrates, showing good linearity relationship between absorbance difference (ΔA) and XO concentrations in the range 0.05-0.5 U/mL (R 2  = 0.998) with a limit of detection (LOD) of 0.019 U/mL. The quantification of XO occurs in 25 min, which is superior to the previously reported and commercial XO assays. The proposed method has been successfully used in the assay of human serum samples, showing its high potential in the field of clinical monitoring., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Antibacterial nanomaterials provide promising alternative strategies to combat the bacterial infection due to deteriorating resistance. However, few have been practically applied due to the lack of clear antibacterial mechanisms. In this work, we selected good-biocompatibility iron-doped CDs (Fe-CDs) with antibacterial activity as a comprehensive research model to systematically reveal the intrinsic antibacterial mechanism. Through energy dispersive spectroscopy (EDS) mapping of in situ ultrathin sections of bacteria, we found that a large amount of iron was accumulated inside the bacteria treated with Fe-CDs. Then, combining the data of cell level and transcriptomics, it can be elucidated that Fe-CDs could interact with cell membranes, enter bacterial cells through iron transport and infiltration, increase intracellular iron levels, trigger increased reactive oxygen species (ROS), and lead to disruption of Glutathione (GSH)-dependent antioxidant mechanisms. Excessive ROS further leads to lipid peroxidation and DNA damage in cells, lipid peroxidation destroys the integrity of the cell membrane, and finally leads to the leakage of intracellular substances resulting in bacterial growth inhibition and death. This result provides important insights into the antibacterial mechanism of Fe-CDs and further provides a basis for the deep application of nanomaterials in biomedicine., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

With the development of social industry and the increase in domestic sewage discharge, pathogenic bacterial contamination in water has become a serious health and environmental problem. It is important to design sewage treatment reagents with effective pathogenic bacterial removal and recyclability. In this work, we developed a nanocomposite, Fe 3 O 4 @TiO 2 @MoS 2 , with once-for-all effects of photocatalytic, magnetic, and peroxidase-like activities for solving the above-mentioned problems. The loading of MoS 2 may cause the band gap of Fe 3 O 4 @TiO 2 to decrease from 3.11 eV to 2.85 eV, demonstrating increased photocatalytic activity under visible light, based on the synergistic impact of Fe 3 O 4 @TiO 2 and MoS 2 . In return, the peroxidase-like activity of Fe 3 O 4 @TiO 2 @MoS 2 was significantly higher than that of Fe 3 O 4 and MoS 2 alone, resulting in the generation of more hydroxyl radicals (˙OH) for combating the drug-resistant broad-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus . The antibacterial mechanism study showed that Fe 3 O 4 @TiO 2 @MoS 2 could effectively inhibit bacterial growth by destroying the bacterial biofilm and genome via the peroxidase-like activity as well as photocatalytic activity. In addition, Fe 3 O 4 @TiO 2 @MoS 2 has excellent paramagnetic properties, which can achieve magnetic recovery after wastewater treatment. Even after three times of recycling, its antibacterial effect can remain above 98.8%.

Reactive oxygen species (ROS) are favorable for antibacterial infection but their overproduction results in serious inflammatory response and aggravates the hypoxic state of the wound tissue, which is detrimental to healing stages of proliferation and remodeling. Here, an atomic-dispersion Fe-doped oxygen-deficient molybdenum oxide MoO 3- X (ADFM) bifunctional nanozyme, featuring implanted peroxidase-like and enhanced catalase-like activity, is developed for decomposing H 2 O 2 into strongly oxidizing hydroxyl radicals (•OH) for prevention of bacterial infection and into plentiful O 2 for healing stages. Therein, the introduction of Fe into MoO 3- X primarily produces an asymmetric electron density difference by elongating the bond length between metal atoms, synchronously stabilizing adsorption of •OH and weakening the adsorption of O 2 . ADFM also shows unimaginably high aqueous dispersity and pH-adaptive ROS regulation in the wound microenvironment, both of which are favorable for ADFM to fully exert enzyme-like activity for timely antibacterial and efficient wound-healing action. ADFM thus achieves efficient healing of drug-resistant bacteria-infected wounds in vivo, at an ultralow dosage of 30 µg mL -1 against 10 6 CFU mL -1 extended spectrum β-lactamases-producing Escherichia coli, exhibiting a wound-healing efficiency of ≈10 mm 2 per day, which sets a benchmark among these noble-metal-free nanozyme-based wound-healing agents., (© 2023 Wiley-VCH GmbH.)

The treatment of acid wastewater to remove organic matter in acid wastewater and recycle valuable resources has great significance. However, the classical advanced oxidation process (AOPs), such as the Fenton reaction, encountered a bottleneck under the conditions of strong acid. Herein, making use of the oxidation properties of CeAY (CeO 2 @acid clay), we built an AOPs reaction system without H 2 O 2 under a strong acid condition that can realize the transformation of organic matter in industrial wastewater. The X-ray photoelectron spectroscopy (XPS) proved that the CeAY based on Ce 3+ as an active center has abundant oxygen vacancies, which can catalyze O 2 to produce reactive oxygen species (ROS). Based on the electron spin-resonance spectroscopy spectrum and radical trapping experiments, the production of •O 2 - and •OH can be determined, which are the essential factors of the degradation of organic compounds. In the system of pH = 1.0, when 1 mg CeAY is added to 10 mL of wastewater, the degradation efficiency of an aniline solution with a 5 mg/L effluent concentration is 100%, and that of a benzoic acid solution with a 100 mg/L effluent concentration is 50% after 10 min of reaction. This work may provide novel insights into the removal of organic pollutants in a strong acid water matrix.

Compacted graphite iron (CGI) has become the most ideal material for automotive engine manufacturing owing to its excellent mechanical properties. However, tools are severely worn during processing, considerably shortening their lifespan. In this study, we prepared a series of cemented carbide-coated tools and evaluated their coating properties in cutting tests. Among all tested coatings, PVD coating made of AlCrN (AC) presented with the best surface integrity and mechanical properties, achieving the best comprehensive performance in the coating test. The AC-coated tool also exhibited the best cutting performance at a low speed of 120 m/min, corresponding to a 60% longer cutting life and the lowest workpiece surface roughness relative to other coated tools. In the cutting test at a high speed of 350 m/min, the CVD double-layer coated tool (MT) with a TiCN inner layer of and an Al 2 O 3 outer layer had a 70% longer cutting life and the lowest workpiece surface roughness relative to other coated tools.

Silver nanoparticles (AgNPs) have been widely recognised as effective antibacterial materials in textiles for enhancing wound healing. However, high loadings of AgNPs are toxic and expensive. Thus, it is ideal to prepare AgNPs in a favourable nanostructure for stable and effective conjugation with the textile carrier by selecting a reductant and stabiliser that contributes to the antibacterial effect. Here, silver nanoparticles/vanadium oxide nanowires (Ag/VO x NWs) were prepared via a one-step reduction strategy using vanadium oxide quantum dots (VO x QDs) as both the reductant and stabiliser. VO x QDs possess antibacterial properties, which aid in minimising the applied silver content while enhancing bactericidal performance. Silver can self-aggregate into nanoparticles as well as promote the formation of vanadium oxide nanowires (VO x NWs). Accordingly, the Ag/VO x NWs exhibited remarkable antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The nanowire structure of the Ag/VO x NWs was favourable for effective loading into a sodium alginate (SA) gel fabric to form a wound dressing. The effective loading of Ag/VO x NWs on SA was conducive to the complete dispersion of the bacteriostatic agent and enhanced the antibacterial activity of AgNPs. The wound dressing efficiently suppressed the growth of wound bacteria and promoted wound healing in vivo., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The emergence of peroxidase (POD)-like nanozyme-derived catalytic therapy has provided a promising choice for reactive oxygen species (ROS)-mediated broad-spectrum antibacterials to replace antibiotics, but it still suffers from limitations of low therapeutic efficiency and unusual addition of unstable H 2 O 2 . Considering that the higher blood glucose in diabetic wounds provides much more numerous nutrients for bacterial growth, a cascade nanoenzymatic active material was developed by coating glucose oxidase (GOx) onto POD-like Fe 2 (MoO 4 ) 3 [Fe 2 (MoO 4 ) 3 @GOx]. GOx could consume the nutrient of glucose to produce gluconic acid (weakly acidic) and H 2 O 2 , which could be subsequently converted into highly oxidative • OH via the catalysis of POD-like Fe 2 (MoO 4 ) 3 . Accordingly, the synergistic effect of starvation and ROS-mediated therapy showed significantly efficient antibacterial effect while avoiding the external addition of H 2 O 2 that affects the stability and efficacy of the therapy system. Compared with the bactericidal rates of 46.2-59.404% of GOx or Fe 2 (MoO 4 ) 3 alone on extended-spectrum β-lactamases producing Escherichia coli and methicillin-resistant Staphylococcus aureus , those of the Fe 2 (MoO 4 ) 3 @GOx group are 98.396 and 98.776%, respectively. Animal experiments showed that the as-synthesized Fe 2 (MoO 4 ) 3 @GOx could much efficiently promote the recovery of infected wounds in type 2 diabetic mice while showing low cytotoxicity in vivo .

Herein, SnTe nanobelts (NBs) with efficient oxidase-mimetic activity were synthesized by the simple electrochemical exfoliation method. A specific inhibition effect of Cl - on the enzymatic behavior of the pure SnTe NBs was discovered, which was accordingly used for establishing a highly feasible, sensitive, selective, and stable Cl - colorimetric assay. The detection concentration range was 50 nM to 1 mM, and the lowest detection limit was 20 nM for Cl - . In addition, a signal on-off-on route based on the SnTe NB nanozyme was designed to realize the reliable and specific detection of Hg 2+ . Therein, the SnTe NBs were grafted with gold nanoparticles to form a hybrid of SnTe/Au, resulting in the depression of the oxidase-like activity, which can then be recovered in the presence of the Hg 2+ due to the formation of a gold amalgam. Especially, it was found that the high concentration of Cl - over 3 mM could again exert suppression influence toward the enzymatic activity of the SnTe/Au-Hg system. Based on the to-love-and-to-kill interaction between Cl - and Hg 2+ , the detection range for Cl - can be extended to 40 to 250 mM. In return, the assays of Cl - could avoid in advance its interference toward the accurate Hg 2+ assays. We systematically clarified the oxidase-like catalytic mechanism of the SnTe-derived nanozyme systems. The as-proposed colorimetry can be successfully applied in practical samples including the sweat, human serum, or seawater/tap water, relating to cystic fibrosis, hyper-/hypochloremia, or environmental control, respectively.

The conventional Fenton reaction has played a vital role in the degradation of pollutants. However, this reaction is prone to forming iron mud, which causes secondary pollution. Additionally, most of the Fenton systems are in homogeneous forms and suffer from intrinsically short lifetimes, hydroxyl radicals that have short diffusion distances (OH) and non-recyclability. Herein, using magnetic composites (Fe 3 O 4 @SiO 2 ) as the carrier and vanadium oxide quantum dots (VO x QDs) as the catalyst, we developed a renewable, heterogeneous, magnetic Fenton-like system for dye degradation in polluted wastewater. The VO x QDs of less than 10 nm showed large specific surface areas, enhanced surface-exposed active atoms, and low toxicity, which are favourable for developing an efficient Fenton-like system. In addition, owing to the electrostatic adsorption between the as-prepared catalyst and the dye molecules, the distance for OH sterilization and decolorization can be significantly reduced, overcoming the shortcomings of the short oxidation distance of OH. Accordingly, the degradation of dyes can be achieved in five seconds. Furthermore, the catalysts can be effectively separated and recycled based on their magnetic features, while the secondary pollution from both the catalysts and the incompletely degraded dye molecules into the environment can be avoided. In addition, the Fe 3 O 4 @SiO 2 is able to maintain a superior morphology, and the composite material (VO x QDs/Fe 3 O 4 @SiO 2 ) maintains more than 90% of the degradation effects even after eight repeated tests., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Nanozyme-based colorimetry was suggested to be a rapid method for biomarker (e.g. glutathione) detection, but this method suffers from lack of efficiency and low-toxicity nanozymes till now. Herein, quantum dots of TiO2 loaded on carbon (TiO2/C-QDs) oxidase-like nanozymes were prepared via a hydrothermal treatment of tiny and few-layered Ti3C2Tx MXene nanosheets, which possess abundant thermodynamic metastable Ti atoms on MXene margins as raw materials for the preparation of TiO2/C-QDs. The oxygen vacancy in TiO2 on the surface of the carbon matrix can facilitate O2 adsorption in the solution and generate reactive oxygen species (ROS), thereby quickly oxidizing 3,3',5,5'-tetramethylbenzidine (TMB) to its oxidized form (TMBox) in the absence of H2O2. After adding glutathione (GSH), TMBox was able to be restored to TMB, which resulted in a corresponding decrease in the UV-vis absorbance value at 652 nm. Furthermore, this assay possesses good selectivity, excellent specificity and high sensitivity (limit of detection: 0.2 μM), which made it possible to efficiently detect GSH in complex biological samples such as human serum.

Electrochemistry belongs to an important branch of chemistry that deals with the chemical changes produced by electricity and the production of electricity by chemical changes. Therefore, it can not only act a powerful tool for materials synthesis, but also offer an effective platform for sensing and catalysis. As extraordinary zero-dimensional materials, carbon-based quantum dots (CQDs) have been attracting tremendous attention due to their excellent properties such as good chemical stability, environmental friendliness, nontoxicity and abundant resources. Compared with the traditional methods for the preparation of CQDs, electrochemical (EC) methods offer advantages of simple instrumentation, mild reaction conditions, low cost and mass production. In return, CQDs could provide cost-effective, environmentally friendly, biocompatible, stable and easily-functionalizable probes, modifiers and catalysts for EC sensing. However, no specific review has been presented to systematically summarize both aspects until now. In this review, the EC preparation methods of CQDs are critically discussed focusing on CQDs. We further emphasize the applications of CQDs in EC sensors, electrocatalysis, biofuel cells and EC flexible devices. This review will further the experimental and theoretical understanding of the challenges and future prospective in this field, open new directions on exploring new advanced CQDs in EC to meet the high demands in diverse applications., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The design and construction of efficient nanozymes are vital for bio/chemo-sensing applications, while the systematic catalytic mechanism study is the prerequisite. Tungsten oxide (WO 3- x ) quantum dots (QDs), an alternative to conventional heavy metal-containing semiconductor QDs, possess peroxidase-like activity but limited catalytic efficiency. Therefore, the functions of the typical oxygenous groups in determining the enzymatic activity of the WO 3- x QDs by target-specifically shielding the carboxyl (-COOH), hydroxyl (-OH), or carbonyl (-C═O) groups, respectively, using a chemical titration method. The results show that the -C═O groups could accelerate the nanozymatic catalysis kinetically, while the -OH ones were the catalytically inhibitive sites, which were further corroborated by the density functional theory (DFT) computations. The application potential of the WO 3- x derivatives with an enhanced catalytic ability was verified via the colorimetric cholesterol sensing. The proposed method based on the benzoic anhydride (BA)-modified WO 3- x QDs with deactivated -OH groups showed a wider linear range and higher sensitivity than those based on the unmodified ones.

Antibiotic resistance is a common phenomenon observed during treatment with antibacterials. Use of nanozymes, especially those with synergistic enzyme-like activities, as antibacterials could overcome this problem, but their synthesis is limited by their high cost and/or complex production process. Herein, vanadium oxide nanodots (VO x NDs) were prepared via a one-step bottom-up ethanol-thermal method using vanadium trichloride as the precursor. VO x NDs alone possess bienzyme mimics of peroxidase and oxidase. Accordingly, highly efficient antibacterials against drug-resistant bacteria can be obtained through synergistic catalysis; the oxidase-like activity decomposes O 2 to generate superoxide anion radical (O 2 - ) and hydroxyl radicals (OH), and the intrinsic peroxidase-like activity can further induce the production of OH from external H 2 O 2 . Consequently, H 2 O 2 concentration could decrease up to four magnitude orders with VO x NDs to achieve an antibacterial efficacy similar to that of H 2 O 2 alone. Wound healing in vivo further confirms the high antibacterial efficiency, good biocompatibility, and application potential of the synergistic antibacterial system due to the "nano" structure of VO x NDs. The method of synthesis of nanodot antibacterials described in this paper is inexpensive, and the results of this study reveal the multi-enzymatic synergism of nanozymes., (Copyright © 2019. Published by Elsevier Inc.)

As the bottleneck of electrochemical overall water splitting, the oxygen evolution reaction (OER) needs efficient catalysts to lower the required overpotential. Electrocatalysts with an amorphous form are highly active but suffer with low structural stability. Poorly crystallized materials with activity like amorphous forms, while maintaining the mechanical robustness of crystalline forms, are expected to be ideal materials. Towards this direction, we, for the first time, developed low-crystalline Fe 5 O 7 (OH)·4H 2 O as an excellent OER electrocatalyst with an overpotential of 269 mV, in order to drive a current density of 100 mA cm -2 in a 1.0 M KOH environment, and this outperforms most of the reported Fe-based electrocatalysts. Notably, its activity can be maintained for at least 100 hours. A one-pot synthesis for the poorly-crystallized material using one of the most abundant metal elements to obtain effective OER catalysis will provide great convenience in practical applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The construction of efficient nanozyme with multienzyme activities in a simple way is vital for the wide biological and chemical applications. Generally, the mimic enzyme activities depend on their sizes, surface states, and materials types. Quantum dots (QDs), one type of zero-dimensional nanomaterials, are much appealing due to their abundant catalytically active surface deficiency. The vanadium oxide (VO x ) is one special transition metal oxides possessing different valence states. Inspired by these views, we synthesized VO x QDs herein via a one-pot top-down ethanol-thermal method using bulk VO 2 as the precursor. The VO x QDs showed not only oxidase- and peroxidase-like activities in ethanol as the main background solution (ethanol-BGS), but also exhibited additional superoxide dismutase mimetic activity in phosphate buffer solution. Furthermore, the TMB-VO x QDs system in the ethanol-BGS produced three distinct colors in the presence of hydrogen peroxide (H 2 O 2 ) at three different concentration gradients (10-90 μM, 0.1-10 mM, and 20-100 mM). Accordingly, we constructed a three-dimensional (3D) coordinate system (3D-CS) by using the three variables: the initial velocities, the maximum absorption values and the visual colors of the enzymatic reaction system. As a result, the rapid detection of H 2 O 2 can be achieved while effectively avoiding the faked appearance due to the inhibition effects to the enzymatic system at too high H 2 O 2 concentration. The applicability of the VO x QDs based 3D-CS was further proved via the facile and accurate H 2 O 2 assays in three different practical samples.

The metal-induced FL quenching of two-dimensional material-derived quantum dots (2D-QDs) has been playing vital roles in optical sensing recently; however, the metal type and concentration are usually chosen arbitrarily based on the maximum FL decrease although several metals may offer similar FL quenching effects towards the same 2D-QDs. Thus, a rational strategy was urgently needed to discover more efficient metal-mediated FL system for further applications. Taking boron nitride QDs (BNQDs) as a promising 2D-QD model, it was discovered that both Fe 3+ and Cu 2+ could quench their FL, which could be further switched on and off upon the addition of pyrophosphate and alkaline phosphatase, respectively. By comparing the percentage of FL quenching and recovery of BNQDs, it was rationally calculated that 300 μM Fe 3+ -mediated FL quenching of BNQDs paved a more efficient way for the sensitive and selective assay of ALP. Quantitative measurement of the ALP activity can be achieved with a low limit of detection of 0.8 U L -1 (S/N ≥ 3) in a wide range between 2 and 200 U L -1 . In addition, the aforementioned ensemble could be exploited to newly construct a 2D-QD-based "INH" logic gate. This approach possessed many superiorities i.e. low cost, simplicity, and high sensitivity.

MoO x quantum dots (QDs) were prepared using a one-step stirring treatment of molybdenum trioxide (MoO 3 ) powder in dimethyl sulfoxide (DMSO). Besides their highly sensitive label-free metal ion and pyrophosphate sensing, the antibacterial activity of the as-prepared MoO x QDs was discovered for the first time.

This review, covering reports published in recent decade from 2004 to 2013, shows how electrochemical (EC) techniques such as voltammetry, electrochemical impedance spectroscopy, potentiometry, coulometry, etc., have made significant contributions in the analysis of minerals such as clay, sulfide, oxide, and oxysalt. It was discussed based on the classifications of both the types of the used EC techniques and kinds of the analyzed minerals. Furthermore, minerals as electrode modification materials for EC analysis have also been summarized. Accordingly, research vacancies and future development trends in these areas are discussed., (Copyright © 2014 Elsevier B.V. All rights reserved.)