Nanozymes are effective antibiotics that use reactive oxygen species (ROS) produced by Fenton/Fenton-like reactions to kill bacteria. However, its activity is still not satisfactory and requires large amounts of hydrogen peroxide ((2)) with side effects on normal tissues. Herein, ultrasmall V8C7 nanodots (NDs) are successfully constructed by the liquid-phase exfoliation method for photothermal-catalytic synergistic an-tibacterial treatment. The prepared V8C7 NDs are horseradish peroxidase (HRP)-like nanozymes that can efficiently catalyze(2) to produce a large amount of ROS. Unlike traditional HRP-like nanozymes, V8C7 NDs can have a good catalytic effect under slightly acidic conditions (pH = 5.5). Moreover, V8C7 NDs have good near-infrared (NIR) absorption and high photothermal conversion efficiency (PTCE, 50.39%), which can be used for photothermal treatment (PTT) of bacteria. In addition, the mild photothermal effect can further enhance the HRP-like catalytic activity of V8C7 NDs, thereby further enhancing the antibacterial performance of V8C7 NDs. In vitro results show that V8C7 NDs can effectively eradicate Escherichia coli ( E. coli, gram-negative) and methicillin-resistant Staphylococcus aureus (MRSA, gram-positive) under laser irradiation and the presence of H2O2, possessing spectral antibacterial properties. More importantly, V8C7 NDs display satisfactory therapeutic effects on wounds infected by MRSA in vivo , and their toxicity is negligible, suggesting that they may have great potential for application as powerful and safe antibacte-rial agents. This work presents a practical antibacterial strategy by combining PTT and catalytic therapy to achieve efficient treatment of bacteria-infected wounds. Statement of significance (1) Ultrasmall V8C7 NDs were prepared by the liquid-phase exfoliation method. (2) V8C7 NDs showed good photothermal, catalytic properties. (3) V8C7 NDs achieved satisfactory photothermal-catalytic synergistic antibacterial treatment.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Despite attracting increasing attention in clinic, non-invasive high-intensity focused ultrasound (HIFU) surgery still commonly suffers from tumor recurrence and even matastasis due to the generation of thermo-resistance in non-apoptotic tumor cells and adverse therapy-induced inflammation with enhanced secretion of growth factors in irradiated region. In this work, inspired by the intrinsic property that the expression of thermo-resistant heat shock proteins (HSPs) is highly dependent with adenosine triphosphate (ATP), dual-functionalized diclofenac (DC) with anti-inflammation and glycolysis-inhibition abilities was successfully co-encapsulated with phase-change dl-menthol (DLM) in poly(lactic-co-glycolic acid) nanoparticles (DC/DLM@PLGA NPs) to realize improved HIFU surgery without causing adverse inflammation. Both in vitro and in vivo studies demonstrated the great potential of DC/DLM@PLGA NPs for serving as an efficient synergistic agent for HIFU surgery, which can not only amplify HIFU ablation efficacy through DLM vaporization-induced energy deposition but also simultaneously sensitize tumor cells to hyperthermia by glycolysis inhibition as well as diminished inflammation. Thus, our study provides an efficient strategy for simultaneously improving the curative efficiency and diminishing the harmful inflammatory responses of clinical HIFU surgery.

Nanozymes have become a new generation of antibiotics with exciting broad-spectrum antibacterial properties and negligible biological toxicity. However, their inherent low catalytic activity limits their antibacterial properties. Herein, Cu single-atom sites/N doped porous carbon (Cu SASs/NPC) is successfully constructed for photothermal-catalytic antibacterial treatment by a pyrolysis-etching-adsorption-pyrolysis (PEAP) strategy. Cu SASs/NPC have stronger peroxidase-like catalytic activity, glutathione (GSH)-depleting function, and photothermal property compared with non-Cu-doped NPC, indicating that Cu doping significantly improves the catalytic performance of nanozymes. Cu SASs/NPC can effectively induce peroxidase-like activity in the presence of H2O2, thereby generating a large amount of hydroxyl radicals (•OH), which have a certain killing effect on bacteria and make bacteria more susceptible to temperature. The introduction of near-infrared (NIR) light can generate hyperthermia to fight bacteria, and enhance the peroxidase-like catalytic activity, thereby generating additional •OH to destroy bacteria. Interestingly, Cu SASs/NPC can act as GSH peroxidase (GSH-Px)-like nanozymes, which can deplete GSH in bacteria, thereby significantly improving the sterilization effect. PTT-catalytic synergistic antibacterial strategy produces almost 100% antibacterial efficiency against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). In vivo experiments show a better PTT-catalytic synergistic therapeutic performance on MRSA-infected mouse wounds. Overall, our work highlights the wide antibacterial and anti-infective bio-applications of Cu single-atom-containing catalysts.

Bacterial infections caused by pathogens have always been a thorny issue that threatens human health, and there is urgent need to develop a new generation of antimicrobial nano-agents and treatments. Herein, biodegradable nickel disulfide (ND) nanozymes as excellent antibacterial agents that integrate excellent photothermal performance, nano-catalysis property, and glutathione (GSH)-depleting function have been successfully constructed. The ND nanozymes can effectively catalyze the decomposition of H2O2 to produce ⋅OH, and the hyperthermia of ND nanozymes generated by photothermal therapy (PTT) can further increase its catalytic activity, which provides rapid and effective bacterial killing effect compared with nano-catalytic treatment or PTT alone. Surprisingly, the ND nanozymes have the ability of GSH consumption, thus enhancing its sterilization effect. Moreover, the ND nanozymes are biodegradable nanomaterials that do not cause any significant toxicity in vivo. Collectively, the ND nanozymes with excellent photothermal performance, catalytic activity, and GSH-depleting function are used for high-efficiency sterilization.

The antimicrobial activity of essential oil of Mentha spicata Linn were qualitatively evaluated using diffusion method.The minimal inhibitory concentration(MIC) of essential oil was measured by UV-visible spect-rophotometry.The results show that the antimicrobial activity of essential oil to the three test strains is:Bacillus subtilisStaphylococcus aureusEscherichia coli.The minimal inhibitory concentration(MIC) to the three strains are:Bacillus subtilis 0.5 μL/mL,Staphylococcus aureus 1.0 μL/mL,Escherichia coli 3.5 μL/mL.

A bacterium strain 6-4-2 with the capacity of degrading cationic red X-GRL was isolated from the sludge samples of anaerobic baffled reactor (ABR) with simulating dye wastewater treatment. The taxonomy status was identified from the morphological and physiological features as well as 16S rDNA sequences analysis. The initial study on characteristic of Cationic Red X-GRL decolorization and degradation of performance was investigated through the static state reactor under facultative anaerobic condition. The result showed the bacterium is Raoultella ornithinolytica. The phylogenetic tree of 6-4-2 revealed it has homology with Raoultella ornithinolytica up to 99%. The structure of Cationic Red was destroyed and the characteristic absorption peak disappeared by the strain. The color removal by strain of Raoultella ornithinolytica 6-4-2 might be primarily attributed to biodegradation, and the biosorption onto the bacterial surfaces was not significant.

The pure PbO 2 electrode and the composite PbO 2 -MnO 2 electrode, modified by adding manganese mineral (75% MnO 2 , Mn powder), were prepared by the high pressure molding method. The effectiveness of the composite electrode for electrochemical degradation of organic pollutants was studied using 4-chlorophenol (4-CP) as a model toxic organic. The experimental results demonstrate that the electrochemical oxidation activity of PbO 2 electrode was improved by the addition of manganese mineral. The enhancement of the electrode for electrochemical oxidation of organics could be attributed to the adsorption and oxygenation of manganese mineral and the production of hydroxyl radicals in the solution. The degradation efficiency of 4-chlorophenol could be raised considerably by reducing pH, prolonging the electrolysis time and increasing the electric power. The degradation accords with stair kinetic process, and the correlative coefficient was above 0.99.

A strain E2 that had a capability to decolorize bromamine acid(BAA)was isolated from the sludge samples of anaerobic baffled reactor(ABR).In the light of its morphological and physiological features as well as its 16S rDNA sequences,it was identified as Enterobacter ludwigii.The most preferable carbon sources and nitrogen sources for decolorization of bromamine acid are glucose and(NH4)2SO4 respectively.The optimal concentration of carbon sources is 1 g/L,and when the concentration of glucose is more than 2 g/L,the decolorization effect is not good.Besides,the optimal concentration of nitrogen sources is 0.5 g/L,and when the concentration increases,the decolorization rate remains basically unchanged.Phosphate has little effect on the decolorization.The optimal growth conditions are pH of 7-8,temperature of 30-35 ℃ and inoculation amount of 5 %.When the concentration of bromamine acid increases,the decolorization rate decreases,but decolorization rate at concentration of 400 mg/L is still up to 80.5 %.In a range of 0-25 g/L,salinity has little effect on the decolorization.The bromanine acid is degraded to form a new product with maximum absorption wavelength at 410 nm.