| 1. |
- Duan, D., et al.
(författare)
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Three-dimensional molecularly imprinted electrochemical sensor based on Au NPs@Ti-based metal-organic frameworks for ultra-trace detection of bovine serum albumin
- 2018
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 261, s. 160-166
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Tidskriftsartikel (refereegranskat)abstract
- A novel three-dimensional molecularly imprinted electrochemical sensor (MIECS) was fabricated for ultra-trace detection of biomacromolecules bovine serum albumin (BSA), which was based on 3D porous electrocatalytic framework materials (AuNPs@NH2-MIL-125(Ti) composites) and graphene modified glassy carbon electrode. The AuNPs supported amino-functionalized Ti-benzenedicarboxylate porous metal-organic frameworks (Au/NH2-MIL-125(Ti)) was prepared by a simple and rapid ultrasonic method. The stable proteins molecularly imprinted polymers (MIPs) films were fabricated by electropolymerization using L-cysteine (L-Cys) as functional monomers and BSA as templates. The monomer L-Cys interact with AuNPs by Au–S bonds and interact with BSA by hydrogen bonding and electrostatic interaction, which was characterized with UV–vis spectra. The morphology of the MIP modified electrode was characterized by scanning electron microscopy, transmission electron microscopy and atomic force microscope. Under the optimal conditions, the 3D MIECS exhibited a wide linear range of 10−18 g mL−1 to 10−12 g mL−1 of BSA and an extremely low detection limit of 4.147 × 10−19 g mL−1. The 3D MIECS has been applied to the assay of BSA in liquid milk samples with satisfying results. © 2017
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| 2. |
- Javed, Rida, et al.
(författare)
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Enhancement mechanism of P dopant on atomically distributed FeN 4 P-C electrocatalyst over a wide pH range
- 2022
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 436
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Tidskriftsartikel (refereegranskat)abstract
- Heteroatom doping plays an essential role in improving the catalytic performance of electrocatalysts for oxygen reduction reaction (ORR). However, how to regulate heteroatom doping remains a significant challenge. This paper develops an efficient strategy by using a novel versatile chelating ligand to enhance P loading and expose more metal single Fe atom active sites of FeN4P-C catalyst. The electron distribution of active center is considerably changed by P doping, which significantly influences the catalytic ORR performance. The dopant P in the FeN4P-C catalyst induces a small number of d-electrons from t2g-orbitals around the Fermi level, making the interaction between Fe active site and O2 slightly more robust than in the FeN4[sbnd]C catalyst, as studied by DFT calculations. The as-prepared FeN4P-C catalyst exhibits excellent catalytic ORR activity in both acidic (with a half-wave potential of 0.760 V vs. RHE) and basic (with a half-wave potential of 0.885 V vs. RHE) conditions, which are superior to those of the commercial Pt/C (20 wt%) catalyst. Furthermore, this catalyst also demonstrates outstanding stability and good hydrogen peroxide and methanol tolerance. A Zinc-air battery(ZAB) assembled using the cathode catalyst has validated the high performance of this catalyst. This study provides an efficient method for generating well-defined single-atom active sites to improve catalytic performance and paves the way to identify coordinated single metal atom sites for electrocatalysis applications.
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| 3. |
- Li, Xianchan, 1982, et al.
(författare)
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Nanopore Opening at Flat and Nanotip Conical Electrodes during Vesicle Impact Electrochemical Cytometry
- 2018
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:3, s. 3010-3019
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Tidskriftsartikel (refereegranskat)abstract
- The oxidation of catecholamine at a microelectrode, following its release from individual vesicles, allows interrogation of the content of single nanometer vesicles with vesicle impact electrochemical cytometry (VIEC). Previous to this development, there were no methods available to quantify the chemical load of single vesicles. However, accurate quantification of the content is hampered by uncertainty in the proportion of substituent molecules reaching the electrode surface (collection efficiency). In this work, we use quantitative modeling to calculate this collection efficiency. For all vesicles except those at the very edge of the electrode, modeling shows that ∼100% oxidation efficiency is achieved when employing a 33 μm diameter disk microelectrode for VIEC, independent of the location of the vesicle release pore. We use this to experimentally determine a precise distribution of catecholamine in individual vesicles extracted from PC12 cells. In contrast, we calculate that when a nanotip conical electrode (∼4 μm length, ∼1.5 μm diameter at the base) is employed, as in intracellular VIEC (IVIEC), the current-time response depends strongly on the position of the catecholamine-releasing pore in the vesicle membrane. When vesicle release occurs with the pore opening occurring far from the electrode, lower currents and partial oxidation (∼75%) of the catecholamine are predicted, as compared to higher currents and ∼100% oxidation, when the pore is close to/at the electrode surface. As close agreement is observed between the experimentally measured vesicular content in intracellular and extracted vesicles from the same cell line using nanotip and disk electrodes, respectively, we conclude that pores open at the electrode surface. Not only does this suggest that electroporation of the vesicle membrane is the primary driving force for catecholamine release from vesicles at polarized electrodes, but it also indicates that IVIEC with nanotip electrodes can directly assess vesicular content without correction. © 2018 American Chemical Society.
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| 4. |
- Li, Y., et al.
(författare)
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A MnO2/Graphene Oxide/Multi-Walled Carbon Nanotubes-Sulfur Composite with Dual-Efficient Polysulfide Adsorption for Improving Lithium-Sulfur Batteries
- 2016
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Ingår i: Acs Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 8:42, s. 28566-28573
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-sulfur batteries can potentially be used as a chemical power source because of their high energy density. However, the sulfur cathode has several shortcomings, including fast capacity attenuation, poor electrochemical activity, and low Coulombic efficiency. Herein, multi-walled carbon nanotubes (CNTs), graphene oxide (GO), and manganese dioxide are introduced to the sulfur cathode. A MnO2/GO/CNTs-S composite with a unique three-dimensional (3D) architecture was synthesized by a one-pot chemical method and heat treatment approach. In this structure, the innermost CNTs work as a conducting additive and backbone to form a conducting network. The MnO2/GO nanosheets anchored on the sidewalls of CNTs have a dual-efficient absorption capability for polysulfide intermediates as well as afford adequate space for sulfur loading. The outmost nanosized sulfur particles are well-distributed on the surface of the MnO2/GO nanosheets and provide a short transmission path for Li+ and the electrons. The sulfur content in the MnO2/GO/CNTs-S composite is as high as 80 wt %, and the as-designed MnO2/GO/CNTs-S cathode displays excellent comprehensive performance. The initial specific capacities are up to 1500, 1300, 1150, 1048, and 960 mAh g(-1) at discharging rates of 0.05, 0.1, 0.2, 0.5, and 1 C, respectively. Moreover, the composite cathode shows a good cycle performance: the specific capacity remains at 963.5 mAh g(-1) at 0.2 C after 100 cycles when the area density of sulfur is 2.8 mg cm(-2).
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| 5. |
- Li, Y., et al.
(författare)
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A three-dimensional core-shell nanostructured composite of polypyrrole wrapped MnOL2/reduced graphene oxide/carbon nanotube for high performance lithium ion batteries
- 2017
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 493, s. 241-248
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Tidskriftsartikel (refereegranskat)abstract
- Manganese oxides are promising anode materials for their high-energy density. However, they suffer from poor rate capability and fast capacity fading. Herein, we construct a three-dimensional (3D) core shell structured polypyrrole (PPy)/MnO2-reduced graphene oxide (rGO)-carbon nanotubes (CNTs) composite via a facile two-step method. In the structure, the CNTs can facilitate fast electron conduction and keep structural integrity. The flexible and conductive rGO nanosheets work as both a reactive material and a carrier for MnO2 in-situ growth. The MnO2 nanosheets well distributed on the rGO/CNTs scaffold favor the energy storage by way of fast Li insertion and extraction. PPy nanoparticles (similar to 10 nm) well wrapped on the MnO2 nanosheets not only enable the interfacial stabilization, but also provide a buffer layer to accommodate the volume expansion. As a result, the as-prepared PPy/Mn02-rGO-CNTs composite exhibits high specific capacity, excellent cycling stability and good rate capability. A reversible specific capacity of 1748.1 mA h g(-1) is achieved at the current density of 100 mA g(-1) after 200 cycles. Even at a high current density of 1000 mA g(-1), the composite still exhibits 941.1 mA h g(-1) after 1200 cycles. The design strategy of the composite can be extended to other high-capacity metal oxide material. (C) 2017 Elsevier Inc. All rights reserved.
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| 6. |
- Li, Y., et al.
(författare)
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Free-standing reduced graphene oxide/MnO2-reduced graphene oxide-carbon nanotube nanocomposite flexible membrane as an anode for improving lithium-ion batteries
- 2017
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 19:11, s. 7498-7505
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Tidskriftsartikel (refereegranskat)abstract
- To solve the barriers of poor rate capability and inferior cycling stability for the MnO2 anode in lithium ion batteries, we present a highly flexible membrane anode employing two-dimensional (2D) reduced graphene oxide sheets (rGO) and a three-dimensional (3D) MnO2-reduced graphene oxide-carbon nanotube nanocomposite (MGC) by a vacuum filtration and thermal annealing approach. All the components in the 2D/3D thin film anode have a synergistic effect on the improved performance. The initial discharge specific capacity of the electrode with the MnO2 content of 56 wt% was 1656.8 mA h g(-1) and remains 1172.5 mA h g(-1) after 100 cycles at a density of 100 mA g(-1). On enhancing the density to 200 mA g(-1), the membrane-electrode still exhibits a large reversible discharging capacity of B948.9 mA h g(-1) after 300 cycles. Moreover, the flexible Li-ion battery with a large area also shows excellent electrochemical performance in different bending positions, which provides the potential for wearable energy storage devices.
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| 7. |
- Li, Y., et al.
(författare)
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Hollow polypyrrole @ MnO2 spheres as nano-sulfur hosts for improved lithium-sulfur batteries
- 2018
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 260, s. 912-920
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Tidskriftsartikel (refereegranskat)abstract
- The lithium-sulfur battery is an ideal energy storage system owing to its high energy density. However, the implementations are still thwarted by dramatic capacity decay caused by the dissolution of lithium polysulfides, the low conductivity and the structural instability of the sulfur cathode originated from the volumetric changes during the charging/discharging process. Here, we design and synthesize polypyrrole (PPy)@MnO2@S spheres with dual core-shell structure. The sulfur nanoparticles (similar to 80 nm) located into the inside of the composite spheres facilitate fast Lithorn storage. The polar MnO2 hollow spheres can not only provide enough inner space for alleviating the volume expansion for sulfur, but also effectively moderate the dissolution of polysulfides by synergistic effect of structural restriction and chemical adsorption. Additionally, the second shell consists of PPy nano-particles serve as conductive frameworks and generate sufficient electrical conduction paths. The initial capacities of PPy@MnO2@S composite are up to 1488.1, 1132.6, 925.7 and 736.7 mAh g(-1) at 0.1 C, 0.2 C, 0.5 C and 1 C, respectively. And a small capacity decay rate of 0.048% per cycle is achieved at the rate of 0.5 C over 500 cycles with an areal density of 3.3 mg cm(-2). The strategy may represent an efficient way to realize excellent performance for Li sulfur batteries. (c) 2017 Elsevier Ltd. All rights reserved.
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| 8. |
- Yang, H., et al.
(författare)
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Molecularly imprinted electrochemical sensor based on bioinspired Au microflowers for ultra-trace cholesterol assay
- 2017
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 0956-5663. ; 92, s. 748-754
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Tidskriftsartikel (refereegranskat)abstract
- A novel imprinted sensor for ultra-trace cholesterol (CHO) detection based on electropolymerized aminothiophenol (ATP) molecularly imprinted polymer (MIP) on a glassy carbon electrode (GCE) modified with dopamine@graphene (DGr) and bioinspired Au microflowers has been developed in this work As the specific recognition element, the bioinspired Au microflowers were formed by Au nanoparticles (AuNPs) and wrapped by bionic polydopamine film (PDA) through electropolymerization method. These excellent biocompatible materials could capture the target CHO effectively. The morphology of the MIP modified electrode was characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The hydrogen bonding interaction between templates and monomers was characterized by ultraviolet spectroscopy. Under the optimal experimental conditions, the sensor's linear response range was between 10(-18) and 10(-13) M, with a detection limit of 3.3x10(-19) M, which was much more sensitive than most available CHO detection methods in previously reports. Moreover, the MIP sensor exhibited high sensitivity for CHO, low interference, and good stability. The human serum samples analysis confirmed the applicability of this MIP sensor to quantitative analysis of ultra-trace CHO.
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| 9. |
- Ye, Daixin, et al.
(författare)
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On the Action of General Anesthetics on Cellular Function: Barbiturate Alters the Exocytosis of Catecholamines in a Model Cell System
- 2018
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Ingår i: Chemphyschem. - : Wiley. - 1439-4235 .- 1439-7641. ; 19:10, s. 1173-1179
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Tidskriftsartikel (refereegranskat)abstract
- General anesthetics are essential in many areas, however, the cellular mechanisms of anesthetic-induced amnesia and unconsciousness are incompletely understood. Exocytosis is the main mechanism of signal transduction and neuronal communication through the release of chemical transmitters from vesicles to the extracellular environment. Here, we use disk electrodes placed on top of PC12 cells to show that treatment with barbiturate induces fewer molecules released during exocytosis and changes the event dynamics perhaps by inducing a less stable fusion pore that is prone to close faster during partial exocytosis. Larger events are essentially abolished. However, use of intracellular vesicle impact electrochemical cytometry using a nano-tip electrode inserted into a cell shows that the distribution of vesicle transmitter content does not change after barbiturate treatment. This indicates that barbiturate selectively alters the pore size of larger events or perhaps differentially between types of vesicles. Alteration of exocytosis in this manner could be linked to the effects of general anesthetics on memory loss.
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| 10. |
- Ye, Daixin, et al.
(författare)
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Using Single-Cell Amperometry and Intracellular Vesicle Impact Electrochemical Cytometry to Shed Light on the Biphasic Effects of Lidocaine on Exocytosis
- 2018
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Ingår i: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 9:12, s. 2941-2947
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Tidskriftsartikel (refereegranskat)abstract
- Single cell amperometry and intracellular vesicle impact electrochemical cytometry were used to examine whether lidocaine can regulate neurotransmitter release or storage for PC12 cells to explain the biphasic effects whereby it can protect neurons and improve cognitive outcome at low concentration, but can cause neurotoxicity at high concentration. We show that lidocaine affects the behavior of PC12 cell exocytosis in a concentration dependent way, which exactly corresponds to its biphasic effects. At a relatively high concentration, it shows a much narrower pore size and a longer-duration fusion pore with less monoamine released than control cells. However, at a relatively low concentration, the fusion pore is open even longer than at high concentration, and with more monoamine released than control cells. Furthermore, intracellular vesicle impact electrochemical cytometry was used to confirm that lidocaine did not change the catecholamine content of the vesicles. These data provide a mechanism for the observed biphasic effects of the drug and suggest that lidocaine influences exocytosis through multiple mechanisms.
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