Latest ArticlesMore and more antibiotics that are difficult to biodegrade have been detected in water environments threatening ecosystems and human health. Therefore, it is urgent to develop efficient water treatment methods to degrade antibiotics. In this work, Co-Fe Prussian blue analogues (PBAs) with different molar ratios were synthesized for peroxymonosulfate (PMS) activation to degrade sulfacetamide (SAM, 10 mg/L). By increasing Co molar ratio, the PMS activation capability and electrochemical properties of PBAs were enhanced. Due to its excellent reactivity (degradation efficiency of 84.2% and mineralization efficiency of 52.79%), cost benefit (electrical energy per order, 0.01019 kWh/L) and lower metal leaching ([Co] = 0.259 mg/L, [Fe] = 0.128 mg/L), PBA-1, the as-prepared catalyst with a molar ratio of cobalt to iron of 1:1, was selected for further study. The radical scavenging experiments and an electron paramagnetic resonance (EPR) trapping experiments were performed and revealed that PBA-1 addition was required to produced •OH and SO4•− from PMS activation. Accordingly, we proposed a PMS activation mechanism and SAM decomposition pathways for PBA-1/PMS reaction system. Besides, a PBA-1@polyvinylidene fluoride (PVDF) catalytic membrane was further prepared to expand the application potential of PBA nanoparticles. The PBA-1@PVDF catalytic membrane was highly effective and exhibited a great reusability; thus, it could be considered for applications in actual water treatment processes.
In this work, we fabricated an efficient pre-catalyst based on (Ni, Co)S2 solid solution with hierarchical architecture and high porosity to boost urea oxidation reaction and electrocatalytic oxidation of organic small molecules. The interaction between Ni and Co can optimize the electronic structure, resulting in the improved conductivity and accelerated charge transfer rate. The 2D/3D architecture can enrich more active species and endow the mass and electron transport to facilitate the surface oxidation and the following catalytic process. Post-structure and catalytic characterizations confirm the surface oxidation of (Ni, Co)S2 during the stability test, and the in-situ formed Co(Ni) based (oxy)hydroxides exhibit superior catalytic activity and facilitated charge transfer ability. As a result, the optimal (Ni, Co)S2 solid solution pre-catalyst displays facilitated catalytic behavior and good stability for multifunctional electrocatalytic oxidation, in which a high conversion of benzyl alcohol (97.50%), a good selectivity to benzoic acid (93.78%) and a satisfied faraday efficiency (91.86%) can be achieved.
Defect engineering has been demonstrated to be an appealing strategy to boost the photocatalytic activity of materials. However, can higher defect concentration bring about higher photocatalytic activity? This is an open question. In this work, BiPO4 photocatalysts with controllable oxygen vacancy concentrations were successfully synthesized. The photocatalytic activity of the obtained BiPO4 photocatalysts was determined by the removal of ciprofloxacin and 4-chlorophenol, as well as CO2 photoreduction. The BiPO4 materials with lower oxygen vacancy concentration could display unexpected higher photocatalytic efficiency. Through the investigation of different factors which may affect the photocatalytic performance, such as crystal structure, morphology, specific surface area, defect, and energy band structure, it can be found that the energy band structure difference was responsible for the enhanced photocatalytic activity.
Hepatotoxicity is a serious problem faced by clinical drugs, and long-term administration or overdose may lead to liver failure and even death of patients. Therefore, developing a reliable detection method for the early diagnosis and therapy of drug-induced liver injury (DILI) has significant meaning. Near-infrared fluorescence (NIRF) and photoacoustic (PA) dual-modality tomography probes can be used for imaging with high sensitivity and high-resolution of disease-related markers in deep tissues. Here, we developed a novel Cys-activated NIRF and PA dual-modality imaging probe (CDR) for early diagnosis of DILI, for the first time. The organic molecular probe CDR could respond rapidly to Cys, resulting in the absorption peak red-shifted from 560 nm to 725 nm, which also leads to the activation of the PA725 signal and NIRF765 signal. In addition, the new probe CDR could be used for NIRF/PA imaging of exogenous and endogenous Cys level in live cells and mice. More importantly, CDR has also been successfully used for in situ detection of Cys in early DILI mice and evaluate the therapeutic effect of NAC. Therefore, the CDR might become a powerful tool to research the physiological effect of Cys and evaluate the degree of DILI.
It is highly desired to accurately and selectively detect and image intracellular L-lysine and pH in biological systems because they could act as the biomarkers in certain abnormal conditions and may give us a warning of the occurrence of diseases. It has been attracted more focuses to design new ratiometric fluorescent probe for monitoring L-lysine and pH to improve detection accuracy. Carbonized polymer dots (CPDs), which possess carbon/polymer hybrid structure rather than pure carbon structure and constitute of a carbon core and large amounts of functional groups/polymer chains on the surface, rise up as a new type of fluorescent nanomaterials and especially display many advantages for bioanalysis. In this study, o-phenylenediamine (o-PD) and poly(styrene-co-maleic anhydride) (PSMA) are used as the precursors to synthesize the desired CPDs through one-step hydrothermal amide method. The prepared CPDs display two well-resolved fluorescence emission bands, i.e., a very weak emission centered at 470 nm in blue region and a strong emission centered at 558 nm in yellow region. It is found that the two emissions are both responsive to L-lysine based on the surface passivation mechanism, whereas, only the yellow emission is responsive to pH due to the protonation/deprotonation process of the amino groups. Based on the different responsive behaviors, ratiometric detection and imaging of L-lysine and pH are achieved. The prepared ratiometric CPDs probe is successfully applied for L-lysine and pH sensing and imaging at two emission channels in live cell and zebrafish with satisfactory results.
The expression of β-lactamase, particularly metallo-β-lactamase (MBL) in bacteria has caused significant resistance to clinically important β-lactam antibiotics, including life-saving carbapenems. Antimicrobial peptides (AMPs) have emerged as promising therapeutic agents to combat antibiotic resistance. However, the cytotoxic AMPs has been one of the major concerns for their applications in clinical practice. Herein, we report a novel cephalosporin-caged AMP, which shows significantly reduced cytotoxicity, hemolytic activity, and antibacterial activity but turns highly active against bacteria upon specific hydrolysis by the antimicrobial resistance-causative β-lactamase. Further investigations demonstrate this β-lactamase-activatable AMP selectively inactivates resistant bacterial pathogens over susceptible bacteria. This strategy should be applicable to other AMPs as a potential solution for the treatment of infectious diseases caused by β-lactamase-expressing pathogenic bacteria.
Pillar[5]arene–modified amphiphilic peptides with varying numbers of guanidiniocarbonylpyrrol (GCP) moieties have been successfully synthesized, which can self-assemble to multivalent cationic superstructures in aqueous solutions. These assembled peptides can condense DNA into various compact multimolecular aggregates to achieve successful intracellular DNA delivery and demonstrate great potential for gene transfection. Transfection efficiencies of the self-assembled superstructures have been evaluated in vitro with HeLa and HEK 293T cells. We demonstrate that GCP moiety could enhance the cell transfection ability, owing to its excellent binding towards cytomembrane. It was also found that subtle structure difference in peptides 2 and 3 could result in distinct transfection efficacy, which makes it possible to gain an in-depth understanding of their structure-activity relationship. This work presents a good example of rational structural design in achieving effective gene transfection vectors.
By developing gem–difluoromethylene allenes as viable partners, regiocontrolled Rh(Ⅲ)-catalyzed redox-neutral C–C coupling/C–N cyclization has been realized to build the pyridin-2(1H)-one motifs with the embedment of a Z-configured monofluoroalkene functionality, in which either (hetero)aromatic or vinylic amides were found to be compatible. Integrated experimental and computational mechanistic studies revealed that a tandem regioselective allene 1,2-insertion/β-H elimination/hydrogen transfer/oxidative addition/cyclization/cis-β-F elimination involving an unconventional Rh(Ⅲ)-Rh(Ⅰ)-Rh(Ⅲ) catalytic cycle accounts for the established transformation. Through further FMO analysis and IGMH maps, a non-covalent weak interaction network between the gem–difluoromethylene part and the OPiv moiety was rationally defined for the unconventional and specific regioselectivity control.
Palm oil mill effluent (POME) is defined as the wastewater that contains high concentrations of organics, nutrients and oil and grease generated from the production process of palm oil. Therefore, proper discharge and management of POME is important to avoid deleterious impact on the environment. In fact, solid waste generation is a precursor for its disposal issues as most of the solid waste generated in developing nations is dumped into landfills. This has led to the threat posed by the generation of landfill leachate (LL). LL is a complex dark coloured liquid consisting of organic matter, inorganic substances, trace elements and xenobiotics. Hence, it is essential to effectively treat the landfill leachate before discharging it to avoid contamination of soil, surface & groundwater bodies. Conventional treatment methods comprises of physical, biological and chemical treatment, however, microalgal-based treatment could also be incorporated. Furthermore, with the benefits offered by microalgae in valorisation, the application of microalgae in POME and leachate treatment as well as biofuel production, is considerably viable. This paper provides an acumen of the microalgae-based treatment of POME and LL, integrated with biofuel production in a systematic and critical manner. The pollutants assimilation from wastewater and CO2 biosequestration are discussed for environmental protection. Cultivation systems for wastewater treatment with simultaneous biomass production and its valorisation, are summarised. The study aims to provide insight to industrial stakeholders on economically viable and environmentally sustainable treatment of wastewaters using microalgae, and eventually contributing to the circular bioeconomy and environmental sustainability.
Exploring highly efficient and non-noble-metal-based electrocatalysts for oxygen evolution reaction (OER) is of great importance not only for water splitting but also for rechargeable metal-air batteries and fuel cells. Herein, we describe a simple strategy to prepare hierarchical Ni@Mn-doped NiO hybrids using flower-like Ni-Mn layered double hydroxides (NiMn-LDHs) as a precursor. After calcination at 400 ℃ for an hour under N2 atmosphere, the flower-like NiMn-LDHs transform to porous microspheres consisting of nanoparticles, in which Ni cores are encapsulated by Mn-doped NiO shells (denoted as Ni@Mn-NiO-400). Benefiting to this unique porous, core-shell structures and element doping, the as-prepared Ni@Mn-NiO-400 hybrid shows a low overpotential of 178 mV at the current density of 10 mA/cm2 and Tafel slope of 52.7 mV/dec in 1 mol/L KOH solution. More significantly, the Ni@Mn-NiO-400 hybrid also demonstrates superior stability of 98.6% after 50 h continuously testing, much higher than pristine NiMn-LDHs and commercial IrO2 catalyst. In addition, theoretical simulation shows that Ni core and Mn doping greatly affect the electronic states and electronic structure of NiO. As a result, Ni@Mn-doped NiO hybrid possesses an optimal adsorption activity towards oxygen species than NiO and undoped Ni@NiO hybrid. Considering the compositional and structural flexibility of LDHs, this work may offer a simple method to prepare other non-noble metal-based electrocatalysts for OER.