BIOSENSORS & BIOELECTRONICS
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2015
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IF 6.409
Qian Zhou,Youxiu Lin,Yuping Lin,Qiaohua Wei,Guonan Chen,Dianping Tang
In this work, a sensitive and specific electrochemical biosensor for lead ion (Pb 2+ ) detection was developed by coupling with synergetic catalysis of porous Au–Pd bimetallic nanoparticles and hemin/G-quadruplex-based DNAzyme. In the presence of target Pb 2+ , the substrate strand was cleaved and the enzyme strand was released. Subsequently, G-rich DNA-labeled Au–Pd bimetallic nanoparticle was linked with the released enzyme strand through the helper DNA . Upon addition of hemin , a large number of hemin/G-quadruplex-based DNAzyme molecules were formed on the electrode to serve as nicotinamide adenine dinucleotide hydrogen (NADH) oxidase and peroxidase mimics. DNAzyme could catalyzed the reduction of H 2 O 2 , generated from NADH in the presence of O 2 , to produce an electrochemical signal when using thionine as the electron mediator. Introduction of porors Au–Pd bimetallic nanoparticles could enhance the detectable signal and cause the increase in the sensitivity. Experimental results showed that the variations (∆ I ) in the cathodic peak currents of the biosensor were linearly dependent on target Pb 2+ concentrations from 1.0 pM to 100 nM with a detection limit (LOD) of 0.34 pM. The excellent performance of the sensing platform indicated its promising prospect as a valuable tool for simple and cost-effective Pb 2+ detection in practical application.
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SOLID STATE SCIENCES
·
2017
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IF 1.811
Chi Him A. Tsang,D.Y.C. Leung
Fabrication of electrocatalyst for direct glucose fuel cell (DGFC) operation involves destructive preparation methods with the use of stabilizer like binder, which may cause activity depreciation. Binder-free electrocatalytic electrode becomes a possible solution to the above problem. Binder-free bimetallic Pd-Pt loaded graphene aerogel on nickel foam plates with different Pd/Pt ratios (1:2.32, 1:1.62, and 1:0.98) are successfully fabricated through a green one-step mild reduction process producing a Pd-Pt/GO/nickel form plate (NFP) composite. Anode with the binder-free electrocatalysts exhibit a strong activity in a batch type DGFC unit under room temperature. The effects of glucose and KOH concentrations, and the Pd/Pt ratios of the electrocatalyst on the DGFC performance are also studied. Maximum power density output of 1.25 mW cm −2 is recorded with 0.5 M glucose/3 M KOH as the anodic fuel, and Pd 1 Pt 0.98 /GA/NFP as catalyst, which is the highest obtained so far among other types of electrocatalyst.
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DALTON TRANSACTIONS
·
2017
·Vol. 46
·期 22
·7210-7218
·
IF 4.029
Wenhui Liu,Qi Wang,Yan Zheng,Shubin Wang,Yan Yan,Yanzhao Yang
In this study, a method of one-step separation and recycling of high purity Pd(II) and Pt(IV) using an ionic liquid, 1-butyl-3-benzimidazolium bromate ([HBBIm]Br), was investigated. The effects of [HBBIm]Br concentration, initial metal concentration, and loading capacity of [HBBIm]Br were examined in detail. It was observed that [HBBIm]Br was a very effective extractant for selectively extracting Pd(II) and precipitating Pt(IV). Through selectively extracting Pd(II) and precipitating Pt(IV), each metal with high purity was separately obtained from mixed Pd(II) and Pt(IV) multi-metal solution. The method of one-step separation of Pd(II) and Pt(IV) is simple and convenient. The anion exchange mechanism between [HBBIm]Br and Pt(IV) was proven through Job's method and FTIR and 1H NMR spectroscopies. The coordination mechanism between [HBBIm]Br and Pd(II) was demonstrated via single X-ray diffraction and was found to be robust and distinct, as supported by the ab initio quantum-chemical studies. The crystals of the [PdBr2 ·2BBIm] complex were formed first. Moreover, the influence of the concentrations of hydrochloric acid, sodium chloride, and sodium nitrate on the precipitation of Pt(IV) and extraction of Pd(II) was studied herein. It was found that only the concentration of H+ could inhibit the separation of Pt(IV) because H+ could attract the anion PtCl62−; thus, the exchange (anion exchange mechanism) between the anions PtCl62− and Br− was prevented. However, both the concentration of H+ and Cl− can obviously inhibit the extraction of Pd(II) because H+ and Cl− are the reaction products and increasing their concentration can inhibit the progress of the reaction (coordination mechanism).
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
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IF 8.1
Zijin Pang,Degang Li,Xinru Wang,Xin Huang,Yu-Shi He,Weimin Zhang,Lipeng Zhang
The electrocatalytic dichlorination (EHDC) shows a promising potential to degrade chlorinated phenols (CPs). It is also a green technology in reducing the corresponding hazardous impact on the environment. In this study, we constructed a catalytic structure which was Pd on a TiO 2 array with oxygen vacancies on carbon fibre paper substrate (Pd/TiO 2 /CFP) by a relatively mild route. Due to the presence of the oxygen vacancies, the resulting strong metal-support interaction (SMSI) effect has been identified which featured a redistribution of spatial charge in Pd/TiO 2 . The electron flow from the oxygen vacancies in the TiO 2 to Pd facilitated the adsorption of Pd with 4-chlorophenol (4-CP) and endowed the Pd metal with an improved chemical reaction kinetics even at a low Pd loading. Experimentally, we studied the dependence of pH, concentration of 4-CP, and working potential on the reaction conditions of EHDC. The results showed that the conversion of 4-CP reached 100 % within 180 min with an apparent rate constant of 2.9 × 10 -2 min −1 and the dominant product was phenol (P). The multi-cycle test illustrated that the Pd/TiO 2 /CFP electrode showed superior stability. The results also revealed that the comprehensive catalytic behavior was much better than those of the Pd/CFP and the TiO 2 /CFP electrodes. The density function theory (DFT) calculations indicated that 4-CP was more preferably absorbed on Pd/TiO 2 /CFP than Pd/CFP due to the SMSI assistance. This study provides a valuable guide in the preparation of precious metal-based electrodes for EHDC with a reduced loading and cost but without performance compromise.
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ACS Biomaterials Science & Engineering
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2024
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IF 5.4
Wenhui Xie,Yilin Lu,Yilin Yuan,Lulu Xiao,Jiaqi Liu,Haofeng Song,Rongcheng Niu,Yanli Liu,Juntang Lin
Metal peroxide nanomaterials as efficient hydrogen peroxide (H2O2) self-supplying agents have attracted the attention of researchers for antitumor treatment. However, relying solely on metal peroxides to provide H2O2 is undoubtedly insufficient to achieve optimal antitumor effects. Herein, we construct novel hyaluronic acid (HA)-modified nanocomposites (MgO2/Pd@HA NCs) formed by decorating palladium nanoparticles (Pd NPs) onto the surfaces of a magnesium peroxide (MgO2) nanoflower as a highly effective nanoplatform for the tumor microenvironment (TME)-responsive induction of ferroptosis in tumor cells and tumor photothermal therapy (PTT). MgO2/Pd@HA NC could be well endocytosed into tumor cells with CD44 expression depending on the specific recognition of HA with CD44, and then, the nanocomposites can be rapidly decomposed in mild acid and hyaluronidase overexpressed TME, and plenty of H2O2 was released. Simultaneously, Pd NPs catalyze self-supplied H2O2 to generate abundant hydroxyl radicals (•OH) and catalyze glutathione (GSH) into glutathione disulfide owing to its peroxidase and glutathione oxidase mimic enzyme activities, while the abundant •OH could also consume GSH in tumor cells and disturb the defense pathways of ferroptosis leading to the accumulation of lipid peroxidation and resulting in the occurrence of ferroptosis. Additionally, the superior photothermal conversion performance of Pd NPs in near-infrared II could also be used for PTT, synergistically cooperating with nanocomposite-induced ferroptosis for tumor inhibition. Consequently, the successfully prepared TME-responsive MgO2/Pd@HA NCs exhibited marked antitumor effect without obvious biotoxicity, contributing to thoroughly explore the nanocomposites as a novel and promising treatment for tumor therapy.
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PHYTOMEDICINE
·
2024
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IF 6.7
Wang Haoyue,Sun Kexiang,Tan Wei Shan,Gao Jiamin,Yuan Luyun,Wen Junkai,Deng Wanli
Background A controlled type of cell death called ferroptosis is linked to increased reactive oxygen species (ROS), lipid peroxidation, and iron buildup. Furthermore, evidence indicates that ferroptosis may act as an immunogenic form of cell death with potential physiological functions in tumors and immunosuppression. Inducing ferroptosis in tumor cells may have the potential to complement cancer immunotherapy strategies. The development of colorectal cancer (CRC) and the poor efficacy of immunotherapy are associated with the crosstalk of cellular ferroptosis. Currently, Icariin (ICA), the main bioactive component extracted from Epimedium , has been shown to inhibit a variety of cancers. However, the specific role and potential mechanism of ICA in regulating ferroptosis in CRC remains unclear. Purpose The aim of this investigation was to clarify the mechanism underlying the anti-CRC cancer properties of ICA and how it induces ferroptosis to enhance immunotherapy. Methods To evaluate cell viability, the Cell Counting Kit-8 (CCK-8) test was utilized. The transwell test and the wound healing assay were used to assess cell migration. A subcutaneous graft tumor model was constructed with C57BL/6 mice using MC38 colorectal cancer cell lines. The inhibitory effect of ICA on CRC, ferroptosis level and immunomodulatory effects were detected by serum biochemical assay, cytokine assay, hematoxylin-eosin (H&E) staining, immunofluorescence staining, CyTOF mass spectrometry flow screening and Western blotting. Western blotting, proteomics, molecular docking and microscale thermophoresis (MST) were used to forecast and confirm ICA's binding and interaction with HMGA2, STAT3, and HIF-1α. Moreover, the levels of lipid peroxidation and ferroptosis were assessed through the use of the C11-BODIPY fluorescent probe, the FerroOrange fluorescent probe, the iron level, the malondialdehyde (MDA) and reduced glutathione (GSH) assay kit, and Western blotting analysis. To assess alterations in mitochondrial structure and membrane potential, transmission electron microscopy (TEM) and JC-1 immunofluorescence were employed. Results It was demonstrated in the current study that ICA treatment inhibits CRC and enhances anti-PD-1 therapy efficacy by inciting ferroptosis. As shown in vitro, ICA inhibits CRC cell proliferation, migration, and apoptosis. As demonstrated in vivo, ICA has a dose-dependent tumor suppressor effect when combined with anti-PD-1, it can significantly inhibit tumor growth, increase the expression of serum TNF-α, IFN-γ, and granzyme B, and promote CD69 + CD8 + T, CD69 + CD8 + Tem, CD69 + CD8 + Teff, TCRβ + CD8 + T, TCRβ + CD8 + T, TCRβ + CD8 + Tem, TCRβ + CD8 + Teff. The inhibitory effect of ICA on CRC was associated with the binding of HMGA2, STAT3, and HIF-1α proteins, which inhibited CRC by increasing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), promoting the accumulation of iron (Fe 2+ ), depletion of reduced glutathione (GSH), inhibiting SLC7A11 and GPX4 expressions, thereby inducing ferroptosis in CRC. As a consequence of ICA-induced ferroptosis, mitochondria are dysfunctional, with increased ROS production, membrane potential depolarization (MMP), and ATP production reduced. This process can be efficiently reversed by the mitochondria-targeted antioxidant Mito-Q. It is noteworthy that the ferroptosis inhibitor liproxstatin-1 (lip-1), anti-CD8, and anti-IFN-γ exhibited a significant inhibitory effect on the level of ferroptosis and antitumor capacity of ICA combined with anti-PD-1. This finding suggests that the antitumor immunopotentiating effect of ICA on anti-PD-1 is dependent on the secretion of IFN-γ-induced ferroptosis of CRC cells by the CD8 + T cell. Conclusion Our study represents the inaugural demonstration of the mechanism whereby ICA exerts anti-CRC effects and synergistically enhances the efficacy of anti-PD-1, inducing mitochondrial damage and leading to ferroptosis. ICA promotes ferroptosis of CRC cells by inducing mitochondrial dysfunction, and ICA combined with anti-PD-1 significantly promotes CD69, TCRβ signalling, activates effector CD8 + T cells to secrete IFN-γ, and achieves immunopotentiation by promoting ferroptosis of CRC cells, thus inhibiting CRC development. This study is built upon existing research into the pharmacodynamic mechanisms of ICA in the context of CRC, and offers a novel therapeutic approach in addressing the issue of CRC immunotherapy potentiation.
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ELECTROCHIMICA ACTA
·
2025
·
IF 5.6
Hui Xiong,Xinyi Hu,Xiaoying Qi,Zhao Jiang
It is essential to design and produce stable, high-activity, and low-cost anode catalysts for direct methanol fuel cells (DMFCs). To improve the efficiency of the methanol oxidation reaction (MOR) in alkaline media, a series of PdM-NbN/C (M=Co, Ni, Cu) bi-component catalysts were synthesized by introducing various oxyphilic metals. Electrochemical evaluations show that the presence of Ni and Co significantly enhances catalytic activity, charge transfer kinetics, CO tolerance, and long-term stability compared to Pd-NbN/C. Among these, PdNi-NbN/C exhibits the highest mass activity of 4806.67 A·g Pd −1 , the lowest onset potential and charge transfer resistance, as determined from electrochemical testing. The rate-determining step (RDS) is identified as the CO ads oxidation reaction. Characterization analysis confirms that the second oxyphilic metals primarily optimize the Pd electronic structure and modulate the interaction between Pd and NbN, making a favorable shift in the d-band centers. Additionally, Ni and Co elements tend to form hydroxides in higher proportions, which aids in the removal of CO ads and accelerates the RDS. The electronic interactions between Pd, Ni, and NbN species are key to the enhanced catalytic performance for MOR. Pd nanoparticles in the electron-deficient condition may aid in the activation of methanol and its intermediates, as indicated by the linear relationship between the mass activities and d-band centers. This work offers important information for the logical design of efficient anode catalysts for DMFCs.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Li-Zhi Huang,Xiang Zhan,Weiguo Chen,Changye Li,Liandong Zhu,Yitao Dai,Jia Deng
Carbon tetrachloride (CT), a common persistent pollutant in groundwater, has attracted widespread attention from environmental researchers. The dechlorination from CT to combustible hydrocarbons not only represents the removal of contaminants, but also offers the possibility of recovering carbon resources from water. In this work, we used the coprecipitation of Fe(II) and Pd(II) to synthesize Pd-Fe hydroxides for the dechlorination of CT. When Pd and Fe dosages were 0.4 and 5 mM respectively, CT with 26 µM concentration can be fast removed within 5 min, and 43.3 % of CH 4 and 11.6 % of C 2 H 6 (mol%) were generated after 110 min. The alkaline condition was more conducive to the complete dechlorination of CT comparing with acidic and neutral conditions. During the olation process, Fe(II) as electron donor transferred electrons to Pd(II) to form Pd(0) clusters. Pd(0) active sites act on the binding of CT and transfer electron to H + /H 2 O to form adsorbed atomic hydrogen (H ads •). The adsorbed CT molecules on the surface of Pd-Fe hydroxides undergo continuous dechlorination to form CH 4 and C 2 H 6 through the attack of H ads • and direct electron transfer. In real groundwater applications, CT was rapidly removed, with CH 4 and C 2 H 6 yields reaching 24.5 % and 4.6 % (mol%), respectively. Encouragingly, incomplete dechlorinated products, including chloroform and dichloromethane, did not show signs of subsequent rebound even after 60 min. Furthermore, Pd-Fe hydroxides also exhibit resistance to the oxidation effects of dissolved oxygen, which demonstrates the promising application prospects.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Yanying Gong,Jing Lin,Chao Yu,Runze Li,Chengchun Tang,Yang Huang
Formic acid (FA) has garnered considerable interest as a sustainable energy source because of its high hydrogen storage capability and convenient transportability. However, efficient dehydrogenation of FA requires highly selective and efficient catalysts. This study explores the potential of C and O co-doped boron nitride (BNC,O) as a support for Pd nanoparticles in FA dehydrogenation. The BNC,O support has been synthesized through high-temperature pyrolysis and subsequently functionalized with −NH2 groups to enhance the dispersion and anchoring of ultrafine Pd nanoparticles (∼2.1 nm). In comparison to the unmodified catalyst, the resulting Pd/BNC,O-A catalyst demonstrates a significant enhancement in catalytic activity for FA dehydrogenation, achieving an initial turnover frequency (TOF) of 522.0 h–1 at 298 K and 1560.9 h–1 at 338 K with nearly 100% hydrogen selectivity. Characterization techniques reveal that the incorporation of C and O heteroatoms and −NH2 groups into the BNC,O support facilitates the formation of small and well-dispersed Pd nanoparticles while also forming a strong metal–support interaction. The −NH2 groups further promote FA dehydrogenation by acting as proton scavengers. This study highlights the promising potential of C and O co-doped, −NH2 functionalized BNC,O as a support for Pd-based catalysts for efficient FA dehydrogenation.
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ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Liang Ding,Roujia Zhang,Peng Zhao,Changsheng Qu
Based on the remediation challenges and practical needs of trichloroethylene (TCE)-contaminated groundwater, this study prepared an Ni-based composite electrode, Pd/Ni(OH) 2 /Ni foam (NF), and evaluates its electrocatalytic degradation effect on TCE in a groundwater environment. Under an applied voltage of –1.3 V versus Ag/AgCl, the TCE removal rate reaches 95% after 3 h of electrolysis. The introduction of Ni(OH) 2 nanoarrays accelerates the electron transport process, shortens the ion transport distance, and significantly increases the electron density of Pd. Furthermore, TCE is rapidly reduced by adsorbed hydrogen radicals on the Pd surface, and the ethane conversion rate reaches 62%. The experimental results show that the electrode can maintain a strong electrocatalytic activity over a wide pH range (3–9) and that it is not affected by common anions, such as Ca 2+ , HCO 3 - , SO 3 2- , or Cl - , in groundwater. Pd/Ni(OH) 2 /NF exhibits a high reactivity after six cycles of use. The remediation mechanism is studied by combining the microscopic characterization of materials, electrochemical activity testing, and process product identification, which provides an effective way of completely degrading chlorinated hydrocarbon pollutants in natural groundwater environment.
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ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
·
2024
·Vol. 68
·期 3
·
IF 4.1
Xiaonan Zhang,Yan Wang,Sanwang Li,Feifan Xie,Hanxi Yi
Bacterial infections, including those caused by Pseudomonas aeruginosa, often lead to sepsis, necessitating effective antibiotic treatment like carbapenems. The key pharmacokinetic/pharmacodynamic (PK/PD) index correlated to carbapenem efficacy is the fraction time of unbound plasma concentration above the minimum inhibitory concentration (MIC) of the pathogen (%fT > MIC). While multiple targets exist, determining the most effective one for critically ill patients remains a matter of debate. This study evaluated meropenem’s bactericidal potency and its ability to combat drug resistance in Pseudomonas aeruginosa under three representative PK/PD targets: 40% fT > MIC, 100% fT > MIC, and 100% fT > 4× MIC. The hollow fiber infection model (HFIM) was constructed, validated, and subsequently inoculated with a substantial Pseudomonas aeruginosa load (1 × 108 CFU/mL). Different meropenem regimens were administered to achieve the specified PK/PD targets. At specified intervals, samples were collected from the HFIM system and subjected to centrifugation. The resulting supernatant was utilized to determine drug concentrations, while the precipitates were used to track changes in both total and drug-resistant bacterial populations over time by the spread plate method. The HFIM accurately reproduced meropenem’s pharmacokinetics in critically ill patients. All three PK/PD target groups exhibited a rapid bactericidal response within 6 h of the initial treatment. However, the 40% fT > MIC and 100% fT > MIC groups subsequently showed bacterial resurgence and resistance, whereas the 100% fT > 4× MIC group displayed sustained bactericidal activity with no evidence of drug resistance. The HFIM system revealed that maintaining 100% fT > 4× MIC offers a desirable microbiological response for critically ill patients, demonstrating strong bactericidal capacity and effective prevention of drug resistance.
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RSC Advances
·
2024
·Vol. 14
·期 18
·12593-12599
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IF 3.9
Junwei Li,Hongshuai Yin,Sisi Liu,Chaofa Xu,Zhixiong Cai
The catalytic performance of a catalyst is significantly influenced by its ability to activate hydrogen. Constructing frustrated Lewis pairs (FLPs) with the capacity for hydrogen dissociation on non-reducible supports remains a formidable challenge. Herein, we employed a straightforward method to synthesize a layered AlOOH featuring abundant OH defects suitable for constructing solid surface frustrated Lewis pair (ssFLP). The results indicated that the AlOOH-80 (synthesized at 80 °C) possessed an appropriate crystalline structure conducive to generating numerous OH defects, which facilitated the formation of ssFLP. This was further evidenced by the minimal water adsorption in the AlOOH-80, inversely correlated with the quantity of defects in the catalyst. As expected, the Pd loaded onto AlOOH (Pd/AlOOH-80) exhibited excellent catalytic activity in hydrogenation reactions, attributed to abundant defects available for constructing ssFLP. Remarkably, the Pd/AlOOH-80 catalyst, with larger-sized Pd nanoparticles, displayed notably superior activity compared to commercial Pd/Al2O3 and Pd/C, both featuring smaller-sized Pd nanoparticles. Evidently, under the influence of ssFLP, the size effect of Pd nanoparticles did not dominate, highlighting the pivotal role of ssFLP in enhancing catalytic performance. This catalyst also exhibited exceptionally high stability, indicating its potential for industrial applications.
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