Coupling Curvature and Hydrophobicity: A Counterintuitive Strategy for Efficient Electroreduction of Nitrate into Ammonia.

The electrochemical upcycling of nitrate (NO3-) to ammonia (NH3) holds promise for synergizing both wastewater treatment and NH3 synthesis. Efficient stripping of gaseous products (NH3, H2, and N2) from electrocatalysts is crucial for continuous and stable electrochemical reactions. This study evaluated a layered electrocatalyst structure using copper (Cu) dendrites to enable a high curvature and hydrophobicity and achieve a stratified liquid contact at the gas-liquid interface of the electrocatalyst layer. As such, gaseous product desorption or displacement from electrocatalysts was enhanced due to the separation of a wetted reaction zone and a nonwetted zone for gas transfer. Consequently, this electrocatalyst structure yielded a 2.9-fold boost in per-active-site activity compared with that with a low curvature and high hydrophilic counterpart. Moreover, a NH3 Faradaic efficiency of 90.9 ± 2.3% was achieved with nearly 100% NO3- conversion. This high-curvature hydrophobic Cu dendrite was further integrated with a gas-extraction membrane, which demonstrated a comparable NH3 yield from the real reverse osmosis retentate brine.

Revolutionizing Airborne Virus Defense: Electromagnetic MXene-Coated Air Filtration for Superior Aerosol Viral Removal.

The COVID-19 pandemic sparked public health concerns about the transmission of airborne viruses. Current methods mainly capture pathogens without inactivation, leading to potential secondary pollution. Herein, we evaluated the inactivation performance of a model viral species (MS2) in simulated bioaerosol by an electromagnetically enhanced air filtration system under a 300 kHz electromagnetic induction field. A nonwoven fabric filter was coated with a 2D catalyst, MXene (Ti3C2Tx), at a coating density of 4.56 mg·cm-2 to absorb electromagnetic irradiation and produce local heating and electromagnetic field for microbial inactivation. The results showed that the MXene-coated air filter significantly enhanced the viral removal efficiency by achieving a log removal of 3.4 ± 0.15 under an electromagnetic power density of 369 W·cm-2. By contrast, the pristine filter without catalyst coating only garnered a log removal of 0.3 ± 0.04. Though the primary antimicrobial mechanism is the local heating as indicated by the elevated surface temperature of 72.2 ± 4 °C under the electromagnetic field, additional nonthermal effects (e.g., dielectrophoresis) on enhanced viral capture during electromagnetically enhanced filtration were investigated by COMSOL simulation to delineate the potential transmission trajectories of bioaerosol. The results provide unique insights into the mechanisms of pathogen control and thus promote alternative solutions for preventing the transmission of airborne pathogens.

Modular Synthesis of Improbable Rotaxanes with All-Benzene Scaffolds.

"Improbable" rotaxanes consisting of interlocked conjugated components represent non-trivial synthetic targets, not to mention those with all-benzene scaffolds. Herein, a modular synthetic strategy has been established using an isolable azo-linked pre-rotaxane as the core module, in which the azo group functions as a tracelessly removable template to direct mechanical bond formations. Through versatile connections of the pre-rotaxane and other customizable modules, [2]- and [3]rotaxanes derived from all-benzene scaffolds have been accomplished, demonstrating the utility and potential of the synthetic design for all-benzene interlocked supramolecules.

Using eDNA to survey amphibians: Methods, applications, and challenges.

In recent years, environmental DNA (eDNA) has received attention from biologists due to its sensitivity, convenience, labor and material efficiency, and lack of damage to organisms. The extensive application of eDNA has opened avenues for the monitoring and biodiversity assessment of amphibians, which are frequently small and difficult to observe in the field, in areas such as biodiversity survey assessment and detection of specific, rare and threatened, or alien invasive species. However, the accuracy of eDNA can be influenced by factors such as ambient temperature, pH, and false positives or false negatives, which makes eDNA an adjunctive tool rather than a replacement for traditional surveys. This review provides a concise overview of the eDNA method and its workflow, summarizes the differences between applying eDNA for detecting amphibians and other organisms, reviews the research progress in eDNA technology for amphibian monitoring, identifies factors influencing detection efficiency, and discusses the challenges and prospects of eDNA. It aims to serve as a reference for future research on the application of eDNA in amphibian detection.

Air nanobubble water improves plant uptake and tolerance toward cadmium in phytoremediation.

Heavy metal contamination continues to be a persistent environmental problem. To address this issue, this study evaluated the impact of air nanobubbles (NBs) in water on the uptake of heavy metals by Alternanthera philoxeroides (A. philoxeroides), a common aquatic plant in China known for its rapid growth, strong vitality, and high capacity for heavy metal remediation. This study found that diluted air NBs (25% concentration) boosted cadmium uptake of A. philoxeroides by 17.39%. They also enhanced plant growth (25-50%) and photosynthetic pigments (10-20%) even at low cadmium levels (0.1 mM). Furthermore, the incorporation of 25% air NBs has been demonstrated to significantly amplify the performance of key antioxidant enzymes, such as superoxide dismutase and catalase, alongside heightened levels of crucial antioxidants such as malondialdehyde. This heightened activity of antioxidant defenses offers a compelling explanation for the potential amelioration of cadmium toxicity and concurrent enhancements in overall plant growth rates. Notably, a comprehensive analysis utilizing the excitation emission matrix-parallel factor analysis (EEM-PARAFAC) technique has revealed alterations in the composition of rhizosphere dissolved organic matter due to the presence of NBs. This ncomposition change of the rhizosphere dissolved organic mattermposition has subsequently exerted an influence on plant complexation processes and the subsequent uptake of cadmium. This study demonstrates that the strategic implementation of air NBs in water systems holds the potential to significantly enhance the plant's ability to detoxify cadmium and improve the uptake of heavy metals during phytoremediation processes.

Unveiling the potential of nanobubbles in water: Impacts on tomato's early growth and soil properties.

Nanobubbles (NBs) in water have been proven to improve plant growth and seed germination, potentially reducing both water and fertilizer consumption. To unravel the promotion mechanism of NBs on plant growth, this study investigated the characteristics of NBs in tap water and their impacts on tomato's early growth, soil chemical properties, enzymatic activity and electrochemical properties of plant roots. Oxygen NBs (ONBs) were found to increase the seed germination by 10 % and plant growth by 30 %-50 % (e.g., stem and diameter), whereas nitrogen NBs (NNBs) only had a significant promotion (7 %-34 %) on plant height. Additionally, compared to control group, irrigation with ONBs increased the peroxidase activities by 500 %-1000 % in tomato leaves, which may increase the expression of genes for peroxidase and promote cell proliferation and plant growth. Moreover, electrical impedance spectroscopy (EIS) revealed that the ONBs could reduce the interfacial impedance due to the increased active surface area and electrical conductivity of root.

Hepatic depletion of nucleolar protein mDEF causes excessive mitochondrial copper accumulation associated with p53 and NRF1 activation.

Copper is an essential component in the mitochondrial respiratory chain complex IV (cytochrome c oxidases). However, whether any nucleolar factor(s) is(are) involved in regulating the mitochondrial copper homeostasis remains unclear. The nucleolar localized Def-Capn3 protein degradation pathway cleaves target proteins, including p53, in both zebrafish and human nucleoli. Here, we report that hepatic depletion of mDEF in mice causes an excessive copper accumulation in the mitochondria. We find that mDEF-depleted hepatocytes show an exclusion of CAPN3 from the nucleoli and accumulate p53 and NRF1 proteins in the nucleoli. Furthermore, we find that NRF1 is a CAPN3 substrate. Elevated p53 and NRF1 enhances the expression of Sco2 and Cox genes, respectively, to allow more copper acquirement in the mDefloxp/loxp, Alb:Cre mitochondria. Our findings reveal that the mDEF-CAPN3 pathway serves as a novel mechanism for regulating the mitochondrial copper homeostasis through targeting its substrates p53 and NRF1.

Pd-Catalyzed C-7 Arylation of Indolines with Aryltriazenes under Mild Conditions.

A palladium-catalyzed direct C-H arylation of indolines at C-7 position has been achieved at near-ambient temperature. The reaction was carried out with aryltriazene as a stable aryl source and electron shuttle to sustainably release aryl radical in situ under the action of promoter, and pyrimidine as a detachable directing group for the synthesis of 7-arylindolines under oxidant- and ligand-free conditions. Notably, this catalytic system can also be applied to the direct and site-selective arylation of tetrahydroquinolines (C-8) and carbazoles (C-1).

Electrosorption, Desorption, and Oxidation of Perfluoroalkyl Carboxylic Acids (PFCAs) via MXene-Based Electrocatalytic Membranes.

MXenes exhibit excellent conductivity, tunable surface chemistry, and high surface area. Particularly, the surface reactivity of MXenes strongly depends on surface exposed atoms or terminated groups. This study examines three types of MXenes with oxygen, fluorine, and chlorine as respective terminal atoms and evaluates their electrosorption, desorption, and oxidative properties. Two perfluorocarboxylic acids (PFCAs), perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) are used as model persistent micropollutants for the tests. The experimental results reveal that O-terminated MXene achieves a significantly higher adsorption capacity of 215.9 mg·g-1 and an oxidation rate constant of 3.9 × 10-2 min-1 for PFOA compared to those with F and Cl terminations. Electrochemical oxidation of the two PFCAs (1 ppm) with an applied potential of +6 V in a 0.1 M Na2SO4 solution yields >99% removal in 3 h. Moreover, PFOA degrades about 20% faster than PFBA on O-terminated MXene. The density functional theory (DFT) calculations reveal that the O-terminated MXene surface yielded the highest PFOA and PFBA adsorption energy and the most favorable degradation pathway, suggesting the high potential of MXenes as highly reactive and adsorptive electrocatalysts for environmental remediation.

Nanoscale Hydrophobicity and Electrochemical Mapping Provides Insights into Facet Dependent Silver Nanoparticle Dissolution.

Metal or metallic nanoparticle dissolution influences particle stability, reactivity, potential fate, and transport. This work investigated the dissolution behavior of silver nanoparticles (Ag NPs) in three different shapes (nanocube, nanorod, and octahedron). The hydrophobicity and electrochemical activity at the local surfaces of Ag NPs were both examined using atomic force microscopy (AFM) coupled with scanning electrochemical microscopy (AFM-SECM). The surface electrochemical activity of Ag NPs more significantly affected the dissolution than the local surface hydrophobicity did. Octahedron Ag NPs with dominant surface exposed facets of {111} dissolved faster than the other two kinds of Ag NPs. Density functional theory (DFT) calculation revealed that the {100} facet elicited greater affinities toward H2O than the {111} facet. Thus, poly(vinylpyrrolidone) or PVP coating on the {100} facet is critical for stabilizing and prevent the {100} facet from dissolution. Finally, COMSOL simulations demonstrated consistent shape dependent dissolution as we observed experimentally.

Electrocatalytic Upcycling of Nitrate Wastewater into an Ammonia Fertilizer via an Electrified Membrane.

Electrochemically upcycling wastewater nitrogen such as nitrate (NO3-) and nitrite (NO2-) into an ammonia fertilizer is a promising yet challenging research topic in resource recovery and wastewater treatment. This study presents an electrified membrane made of a CuO@Cu foam and a polytetrafluoroethylene (PTFE) membrane for reducing NO3- to ammonia (NH3) and upcycling NH3 into (NH4)2SO4, a liquid fertilizer for ready-use. A paired electrolysis process without external acid/base consumption was achieved under a partial current density of 63.8 ± 4.4 mA·cm-2 on the cathodic membrane, which removed 99.9% NO3- in the feed (150 mM NO3-) after a 5 h operation with an NH3 recovery rate of 99.5%. A recovery rate and energy consumption of 3100 ± 91 g-(NH4)2SO4·m-2·d-1 and 21.8 ± 3.8 kWh·kg-1-(NH4)2SO4, respectively, almost outcompete the industrial ammonia production cost in the Haber-Bosch process. Density functional theory (DFT) calculations unraveled that the in situ electrochemical conversion of Cu2+ into Cu1+ provides highly dynamic active species for NO3- reduction to NH3. This electrified membrane process was demonstrated to achieve synergistic nitrate decontamination and nutrient recovery with durable catalytic activity and stability.

ROS-mediated photoaging pathways of nano- and micro-plastic particles under UV irradiation.

Reactive oxygen species (ROS) generation is considered as an important photoaging mechanism of microplastics (MPs) and nanoplastics (NPs). To elucidate the ROS-induced MP/NP aging processes in water under UV365 irradiation, we examined the effects of surface coatings, polymer types and grain sizes on ROS generation and photoaging intermediates. Bare polystyrene (PS) NPs generated hydroxyl radicals (•OH) and singlet oxygen (1O2), while coated PS NPs (carboxyl-modified PS (PS-COOH), amino-modified PS (PS-NH2)) and PS MPs generated fewer ROS due to coating scavenging or size effects. Polypropylene, polyethylene, polyvinyl chloride, polyethylene terephthalate and polycarbonate MPs only generated •OH. For aromatic polymers, •OH addition preferentially occurred at benzene rings to form monohydroxy polymers. Excess •OH resulted in H abstraction, CC scission and phenyl ring opening to generate aliphatic ketones, esters, aldehydes, and aromatic ketones. For coated PS NPs, •OH preferentially attacked the surface coatings to result in decarboxylation and deamination reactions. For aliphatic polymers, •OH attack resulted in the formation of carbonyl groups from peracid, aldehyde or ketone via H abstraction and CC scission. Moreover, 1O2 might participate in phenyl ring opening for PS NPs and coating degradation for coated PS NPs. This study facilitates understanding the ROS-induced weathering process of NPs/MPs in water under UV irradiation.

Percutaneous Full-Endoscopic Anterior Transcorporeal Cervical Discectomy for the Treatment of Cervical Disc Herniation: Surgical Design and Results.

BACKGROUND: Studies that focus on percutaneous full-endoscopic anterior transcorporeal cervical discectomy (PEATCD) have rarely been reported. Therefore, the available data on the surgical design of PEATCD and related clinical outcomes are very limited. OBJECTIVES: To design a surgical plan for PEATCD and to evaluate its clinical efficacy in clinical application. STUDY DESIGN: A retrospective cohort study. SETTING: A center for spine surgery, rehabilitation department and pain medicine. METHODS: Based on the size and precise location of the disc protrusions on magnetic resonance imaging (MRI), the diameter and direction of the bone channel were designed to make a surgical plan for PEATCD. A total of 26 patients with central/paracentral cervical disc herniation (CDH) who underwent PEATCD through the designed surgical plan from October 2015 to September 2016 were enrolled in the retrospective study. Clinical outcome evaluations included Visual Analog Scale (VAS) scores, Japanese Orthopedic Association (JOA) scores, and the modified Macnab criteria. Radiologic follow-up included cervical computerized tomography (CT) and MRI evaluations. RESULTS: The diameter of the designed bone channel was about 7.5 mm, and the direction was from the upper edge of the lower endplate obliquely toward the disc protrusion. Through the designed surgical plan, 26 cases of discectomy were successfully completed. The average operation time was 91.50 ± 16.80 min, and the average hospital stay was 4.07 ± 0.84 days. All patients were followed for an average of 19.61 ± 4.04 months. The postoperative VAS and JOA scores were significantly improved compared with the preoperative scores (P < 0.0001). Clinical efficacy at the final follow-up was evaluated by the modified Macnab criteria, and the excellent and good rate was 92.31%. Postoperative MRI showed that the disc protrusion was completely removed, and CT showed no collapse of the vertebral body. LIMITATIONS: This study has several limitations, including the lack of a control group, the small sample size, and the unavoidable nature of the single-center study design. CONCLUSIONS: Based on the size and location of the disc protrusion on MRI, the diameter and direction of the bone channel are designed, which is conducive to have enough space under the full-endoscopic field of view to completely expose and remove the disc protrusion, to avoid residuals, and to ensure that PEATCD achieves good therapeutic results. TRIAL REGISTRATION: The study was registered at Chinese Clinical Trial Registry (ChiCTR1900027820).

Electrochemically Selective Ammonia Extraction from Nitrate by Coupling Electron- and Phase-Transfer Reactions at a Three-Phase Interface.

As an attractive alternative to the Haber-Bosch process, an electrochemical process for nitrate (NO3-) reduction to ammonia (NH3) has made great strides in the development of advanced electrocatalysts to suppress the unavoidable H2 evolution reaction (HER) and side production of N2. However, isochronous NH3 separation and recovery from the mother liquor, especially wastewaters, are awfully neglected in state-of-the-art electrochemical systems. Here, we designed electrochemical three-phase interfaces constructed by a CoP cathode and a flat-sheet gas membrane to achieve NO3- reduction to ammonia and simultaneous NH3 recovery in the form of (NH4)2SO4 from wastewaters. The partial current density for ammonia yield and its recovery rate were 37.3 mA cm-2 and 306 g NH3-N m-2 day-1, respectively, accompanying 100% NO3- removal and 99.7% NH3 extraction. By favoring the originally unfavored side reaction HER, it served as the driving force for NH3 separation from the wastewater through gas stripping and membrane separation at the three-phase interfaces. Unexpectedly, the timely NH3 separation could also promote the reduction of NO3- to ammonia due to the release of much more active sites. From these, we envision that the present electrochemical process can be routinely employed as an effective strategy to address energy and environmental issues with NH3 recovery from NO3- wastewater.

Photocatalytically reductive defluorination of perfluorooctanoic acid (PFOA) using Pt/La2Ti2O7 nanoplates: Experimental and DFT assessment.

To enable efficient degradation of perfluorooctanoic acid (PFOA), we prepared and investigated a nanosheet photocatalyst (Pt/La2Ti2O7). Doping platinum nanoparticles on La2Ti2O7 varied the band structure and improved the photocatalytic activity due to the enhanced charge separation. Methanol as the electron donor and sacrificial reagent significantly promoted the photocatalytically reductive degradation of PFOA that reduced by 40% within 180 min under UV254 irradiation (1 mW∙cm2). The density functional theory calculations were used to analyze the effects of Pt doping and band structures on interfacial electron transfer and degradation pathways. As opposed to photocatalytic oxidation, this UV/Pt/La2Ti2O7/CH3OH photocatalysis could abstract electrons from methanol and convert to free reactive radicals and photo-generated electrons to reductively defluorinate PFOA and potentially other polyhalogenated or perhalogenated organic compounds.

Xanthatin alleviates airway inflammation in asthmatic mice by regulating the STAT3/NF-κB signaling pathway.

Here, we aimed to investigate the role of Xanthatin in asthma and its underlying mechanism. BALB/c mice were treated with ovalbumin (OVA) to establis a mouse model of asthma. Our results showed that OVA injection significantly increased inflammatory cell infiltration and goblet cell hyperplasia in lung issues, while Xanthatin treatment and STAT3 inhibitor C188-9 administration relieved these symptoms. Moreover, OVA-induced OVA-specific immunoglobulin E level in serum and the number of total cell, macrophages, lymphocytes, neutrophils, and eosinophils in bronchoalveolar lavage fluid (BALF) were markedly reduced by Xanthatin treatment and signal transducer and activator of transcription 3 (STAT3) inhibition. Additionally, Xanthatin treatment and STAT3 inhibition was also significantly decreased the levels of inflammatory cytokines in BALF in asthmatic mice. We further demonstrated that the STAT3/nuclear factor-kappaB (NF-κB) pathway was blocked by Xanthatin in asthmatic mice. Overall, we conclude that Xanthatin attenuates airway inflammation in asthmatic mice through blocking the STAT3/NFκB signaling pathway, indicating the potential of Xanthatin as a useful therapeutic agent for asthma.

Effects of domestic handling of drinking water on halogenated acetaldehydes.

Halogenated acetaldehydes (HALs) are widely considered to be the third largest group of identified disinfection by-products (DBPs) by weight in drinking water. In this study, we evaluated various scenarios for the domestic handling of drinking water and their effects on HALs. Two drinking water systems (DS1 and DS2) were selected for this case study. First, tap water samples that were collected in DS1 at different time and from different locations were subjected to three domestic handling scenarios: boiling, domestic filtration using a point-of-use device with a new filter followed by refrigeration, and refrigeration in a covered glass pitcher. In the last two scenarios, the maximum storage (refrigeration) time was 24 h. Second, two water samples each from DS1 and DS2 were collected to investigate the effects that heating water to different temperatures has on HALs. According to the results, boiling the water effectively removed most HALs except dichloroacetaldehyde (DCAL), which increased. In contrast to the variable behaviors of HALs after boiling, all HALs were consistently and significantly reduced by domestic filtration. However, the overall removal efficiency of HALs from filtration (65%) was considerably lower than that from boiling (85%). Finally, refrigeration had no significant impact on the overall concentration of total HALs. However, chloral hydrate levels increased in unfiltered water after refrigeration, likely due to the reaction of chlorine residuals and precursors present in water. Therefore, boiling and domestic filtering of tap water may be recommended for the removal of HALs prior to consuming tap water.

[Research progress in minimally invasive treatment of cervical nerve root canal stenosis under total endoscope].

OBJECTIVE: To review the research progress of total endoscopic minimally invasive technique in treating cervical nerve root canal stenosis (CNRCS). METHODS: The related literature at home and abroad was extensively reviewed. The research history, current situation, research progress, advantages and disadvantages of minimally invasive treatment of CNRCS under total endoscope were summarized. RESULTS: In recent years, with the continuous development of minimally invasive technique of total endoscope in spine surgery, the surgical treatment methods are also constantly innovated. Compared with the traditional open surgery, minimally invasive treatment of CNRCS under total endoscope can obtain better effectiveness, keep the stability of the cervical segment to the maximum extent, reduce the impact on the activity of the cervical spine and the occurrence of related surgical complications, which is an effective minimally invasive technology. CONCLUSION: The minimally invasive treatment of CNRCS under total endoscope has achieved some results, which is expected to be one of the indispensable means to treat CNRCS, but it still needs to be improved.

Synergistic effects of quenching agents and pH on the stability of regulated and unregulated disinfection by-products for drinking water quality monitoring.

Quenching agents (QAs) are widely used in order to prevent the additional formation of disinfection by-products (DBPs) during the sample holding time. In addition, DBP levels are usually stabilized by adjusting the pH of water samples. Previous studies have mostly focused on the individual effects of QAs or of pH on the stability of DBPs in water samples. Considering that disinfectant quenching and pH adjustments are applied simultaneously during routine analyses, it is more appropriate to evaluate the stability of DBPs with all the chemicals (e.g., disinfectants, QAs, buffers) present in the water. This study investigated the synergistic effects of different QAs (ascorbic acid, ammonium chloride, or no quenching) and pH adjustment (3-9) strategies on the stability of different classes of DBPs (i.e., trihalomethanes (THMs), halogenated acetaldehydes (HALs), haloacetonitriles (HANs), haloketones (HKs), and halonitromethane (HNM)). Sample preservation conditions that did not include a QA were shown to be inadequate for GC-ECD analysis, due to interference problems. Ammonium chloride was found to be effective for most DBPs. However, some HALs continued to form in the presence of chloramine, which is a by-product of dechlorination using ammonium chloride. Conversely, using ascorbic acid efficiently inactivated residual chlorine, providing a clean chromatographic baseline. Based on the results of this study, we recommend the use of ascorbic acid for quenching and sulfuric acid for acidifying (pH 3.5) samples. Considering the instability of some DBPs in water matrices over long periods (i.e., 14 days), samples should be processed as soon as possible after collection.

Magnetic stir bars with hyperbranched aptamer as coating for selective, effective headspace extraction of trace polychlorinated biphenyls in soils.

It is challenging to greatly increase of the extraction selectivity and efficiency by stir bar sorptive extraction of ultra-trace polychlorinated biphenyls (PCBs) in complex environmental matrix, e.g., soils. To fulfill this purpose, one of the critical works is to prepare some coatings with high selectivity, adsorptive capacity and reusability. It is also important to develop some green, simple methods for preperation the coatings. In this work, a kind of highly efficient and bioactive coating based on hyperbranched aptamer (HB-Apt) was constructed via hybridization chain reaction (HCR). Then, the HB-Apt was coated on a magnetic stir bar and applied to headspace extraction of PCB72 and PCB106 in soils. The core-shell gold magnetic particles (Fe3O4@AuNPs, AuMNPs for short) was employed as the substrate to immobilize the HB-Apt. The extracted PCBs on the stir bar could be easily eluted in ethanol by stirring, and then sampled in gas chromatography-mass spectrometry (GC-MS) for qualification. The ultra-low detection limit (0.003-0.005 ng•g-1), good linearity (0.01-500 ng•g-1, R2≥0.994) and reproducibility (RSD: 4.58-6.53%) were obtained. Compared with the common aptamer coating, the HB-Apt coating exhibited good selectivity and higher extraction capacity. The results might be related to the fact that there are more aptamer fragments grated on the HB-Apt coating than those of the common aptamer coating. The magnetic stir bar can not only be employed for easy headspace extraction, but also facilitate separation and elution. Moreover, the coating could be recycled for at least 60 times before recoveries of the PCB72 and PCB106 in the spiked samples drop below 90%. All these indicated that the assay is simple, robust, environment friendly and promising for detection of trace PCBs in complex environmental samples.