Synthesis of free‐standing two‐dimensional (2D) conjugated covalent organic framework (COF) films linked by C−C bonds is highly desirable. Now a very simple and mild strategy has been developed to ...synthesize them by Suzuki polymerization on a water–toluene interface in a refrigerator. The versatility of this strategy was confirmed by the successful synthesis of two different 2D‐COF films: a porous graphene and a porphyrin‐contained 2D‐COF. Both 2D‐COF films have large lateral size and their crystalline domains were visualized by high resolution TEM. Based on the wide compatibility of Suzuki reaction, our breakthrough work opened a door for the synthesis of various 2D conjugated COF films. For application studies, the porous graphene exhibits a good carrier mobility, which is much higher than −C=N− linked 2D COF films and a good catalytic activity for hydrogen evolution reaction, which is comparable with nitrogen‐ or phosphorus‐doped graphene.
COFs at the interface: A very simple and mild strategy to synthesize 2D conjugated COF films was developed. The method uses Suzuki polymerization on a liquid–liquid interface at low temperature (2 °C).
Transition metal oxides or (oxy)hydroxides have been intensively investigated as promising electrocatalysts for energy and environmental applications. Oxygen in the lattice was reported recently to ...actively participate in surface reactions. Herein, we report a sacrificial template-directed approach to synthesize Mo-doped NiFe (oxy)hydroxide with modulated oxygen activity as an enhanced electrocatalyst towards oxygen evolution reaction (OER). The obtained MoNiFe (oxy)hydroxide displays a high mass activity of 1910 A/g
at the overpotential of 300 mV. The combination of density functional theory calculations and advanced spectroscopy techniques suggests that the Mo dopant upshifts the O 2p band and weakens the metal-oxygen bond of NiFe (oxy)hydroxide, facilitating oxygen vacancy formation and shifting the reaction pathway for OER. Our results provide critical insights into the role of lattice oxygen in determining the activity of (oxy)hydroxides and demonstrate tuning oxygen activity as a promising approach for constructing highly active electrocatalysts.
The chemical composition, size, shape and surface characteristics of nanoparticles affect the way proteins bind to these particles, and this in turn influences the way in which nanoparticles interact ...with cells and tissues. Nanomaterials bound with proteins can result in physiological and pathological changes, including macrophage uptake, blood coagulation, protein aggregation and complement activation, but the mechanisms that lead to these changes remain poorly understood. Here, we show that negatively charged poly(acrylic acid)-conjugated gold nanoparticles bind to and induce unfolding of fibrinogen, which promotes interaction with the integrin receptor, Mac-1. Activation of this receptor increases the NF-κB signalling pathway, resulting in the release of inflammatory cytokines. However, not all nanoparticles that bind to fibrinogen demonstrated this effect. Our results show that the binding of certain nanoparticles to fibrinogen in plasma offers an alternative mechanism to the more commonly described role of oxidative stress in the inflammatory response to nanomaterials.
A single nanoparticle platform has been developed through the modular and controlled layer-by-layer process to codeliver siRNA that knocks down a drug-resistance pathway in tumor cells and a ...chemotherapy drug to challenge a highly aggressive form of triple-negative breast cancer. Layer-by-layer films were formed on nanoparticles by alternately depositing siRNA and poly-l-arginine; a single bilayer on the nanoparticle surface could effectively load up to 3500 siRNA molecules, and the resulting LbL nanoparticles exhibit an extended serum half-life of 28 h. In animal models, one dose via intravenous administration significantly reduced the target gene expression in the tumors by almost 80%. By generating the siRNA-loaded film atop a doxorubicin-loaded liposome, we identified an effective combination therapy with siRNA targeting multidrug resistance protein 1, which significantly enhanced doxorubicin efficacy by 4 fold in vitro and led to up to an 8-fold decrease in tumor volume compared to the control treatments with no observed toxicity. The results indicate that the use of layer-by-layer films to modify a simple liposomal doxorubicin delivery construct with a synergistic siRNA can lead to significant tumor reduction in the cancers that are otherwise nonresponsive to treatment with Doxil or other common chemotherapy drugs. This approach provides a potential strategy to treat aggressive and resistant cancers, and a modular platform for a broad range of controlled multidrug therapies customizable to the cancer type in a singular nanoparticle delivery system.
Bismuth(III) oxybromide (BiOBr) is a typical photocatalyst with a unique layered structure. However, the response of BiOBr to visible light is not strong enough for practical application. Moreover, ...the charge separation efficiency of BiOBr still needs to be improved. In this study, series of Au-doped BiOBr photocatalysts was prepared through a facile one-step hydrothermal method. The as-prepared Au.sub.0.3 -BiOBr nanosheets exhibited an excellent electrochemical performance. The charge separation efficiency of Au.sub.0.3 -BiOBr nanosheets was enhanced by 18.5 times compared with that of BiOBr. The intrinsic photocatalytic activity of Au.sub.0.3 -BiOBr nanosheets in the degradation of tetracycline hydrochloride was approximately twice higher than that of BiOBr under visible light irradiation. In addition, three pathways were identified for the photocatalytic degradation and mineralization of tetracycline hydrochloride, which involve four reactions: hydroxylation, demethylation, ring opening and mineralization. Accordingly, this study proposes a feasible and effective Au-doped BiOBr photocatalyst, and describes a promising strategy for the design and synthesis of high-performance photocatalysts.
Ionic liquids (ILs) have appeared as the most promising electrolytes for lithium-ion batteries, owing to their unique high ionic conductivity, chemical stability and thermal stability properties. ...Poly(ionic liquid)s (PILs) with both IL-like characteristic and polymer structure are emerging as an alternative of traditional electrolyte. In this review, recent progresses on the applications of IL/PIL-based semi-solid state electrolytes, including gel electrolytes, ionic plastic crystal electrolytes, hybrid electrolytes and single-ion conducting electrolytes for lithium-ion batteries are discussed.
It is promising to recover lactic acid (LA) from fermentation of food waste (FW). In this study, pH and temperatures were investigated comprehensively to find their effects on LA fermentation, and ...microbial analyses were used to take insight to the variation of LA production. The results showed that mesophilic fermentation benefited hydrolysis and acidification, leading to a high yield of LA, while thermophilic conditions restricted other producers at low pH, leading to a high purity of LA. Lactobacillus amylolyticus was the main LA producer under thermophilic conditions, but Thermoanaerobacterium thermosaccharolyticum boomed at pH 5.0–6.0 and it converted LA partly to butyric acid. Simultaneously, Bacillus coagulans also increased and improved the optical purity (OP) of L-LA. From a series of this study, an operational condition of pH 5.5 and temperature of 52 °C would be potentially suitable for lactate fermentation of FW with high purity of 89%, while a stable LA production with an OP of 68% was achieved at 55 °C and pH 6.0.
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•Mesophilic fermentation benefits hydrolysis and acidification of food waste.•Thermophilic fermentation prompted lactic acid purity but limited the yield at low pH.•Small changes in temperature affect the spectrum of fermentation products.•52 °C and pH 5.5 were the best condition for lactic acid production with high purity.•55 °C and pH 6.0 favor the production of L-lactic acid with high optical purity.
•Semi-continuous electro-fermentation was used for food waste treatment.•The electro-fermentation system accelerated the stabilization of anaerobic digestion.•The electro-fermentation system enhanced ...methane production by 26.3%.•The contributions of electrodes and current were distinguished.•Direct reduction of CO2 to CH4 through electrode reactions was limited.
Electro-fermentation is used as an alternative to conventional anaerobic digestion to enhance system stability and methane production from food waste. In particular, the contributions of electrode materials and an electric current are analyzed separately. The results showed that the introduction of electrodes (conductive carbon brushes without applied voltage) rapidly decreased the average concentration of volatile fatty acids (VFAs) from 6617 mg/L to 174 mg/L quickly, accelerated stabilization of digestion system, and improved methane production by 13.5%. When low voltage was supplied, the VFAs concentration declined to 129 mg/L, and methane production increased by 26.3%. Electric current stimulated the growth of hydrogenotrophic methanogens, but acetotrophic Methanosaeta still made up 27.6–61.9% of archaeal community. Geobacter occurred at the cathode with a low abundance. The energy contained in incremental methane was 4.55 times the consumption of electric energy, indicating the enhanced methanogenesis was mainly attributed to the improved digestion environment.
Two-phase anaerobic digestion (TPAD) is a commonly used method for recovering energy from food waste, even though the relationship between fermentation type and methane production has not to be ...thoroughly investigated. In this study, homolactic acid fermentation (HOLA), heterolactic acid fermentation (HELA), butyric acid fermentation (BUA), and mixed acid fermentation (MA) were used in the first phase, and the corresponding methane production levels were compared. HELA and MA resulted in the maximum methane yields of 290 and 287 ml per gram chemical oxygen demand (COD), respectively, but they were not significantly higher than the yield of 279 ml/g COD from single-phase anaerobic digestion (SPAD). During methanogenesis, BUA led to the fastest hydrolysis and methane production rates, followed by MA and HELA. In spite of the similar potential for methane production and energy recovery, TPAD using either BUA, MA, or HELA as the fermentation phase exhibited at least 50% greater methane production efficiency than SPAD. Overall, HELA and MA were found to be the best choices in terms of treatment efficiency and energy recovery.
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•Effect of fermentation types on methanogenesis was summarized in food waste digestion.•Different processes resulted in similar cumulative methane yields.•Two-phase anaerobic digestion (TPAD) accelerated methane production significantly.•Heterolactic acid fermentation and mixed acid fermentation are recommend for TPAD.
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