BienzymaticAcetylcholinesteraseandCholine OxidaseImmobilized Biosensor Based on a Phenyl Carboxylic Acid-Grafted Multiwalled Carbon Nanotube

Bienzymaticacetylcholinesterase(AChE) andcholine oxidase(ChOx) immobilized biosensor based on a phenyl carboxylic acid-grafted multiwalled carbon nanotube (MWNT) modified glass carbon electrode (GCE) and carbon-screen printed electrode (SPE) was fabricated for acetylcholine detection in human blood samples. Phenyl carboxylic acid-modified MWNT supports were prepared by electrochemical polymerization of 4-carboxyphenyl diazonium salts, which were synthesized by an amine group and sodium nitrite, on the surface of the MWNT-modified GCE and SPE in 0.1 M PBS. The successful fabrication of the AChE-ChOx-immobilized biosensor was confirmed via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The sensing range of the biosensor based on a GCE and SPE was 1.0~10 μM and 10~100 μM, respectively. The interfering effect of 0.1 M L-ascorbic acid, 0.1 M L-cysteine, and 0.1 M uric acid to 0.1 M acetylcholine was 3.00%, 9.00%, and 3.00%, respectively. Acetylcholine in a human blood sample was detected by the AChE-ChOx-immobilized biosensor.

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Electrochemical Analysis of Architecturally Enhanced LiFe0.5Mn0.5PO4 Multiwalled Carbon Nanotube Composite

Journal of Nanotechnology ◽

10.1155/2021/6532348 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Sabelo Sifuba ◽

Shane Willenberg ◽

Usisipho Feleni ◽

Natasha Ross ◽

Emmanuel Iwuoha

Keyword(s):

Electron Transfer ◽

Carbon Nanotube ◽

Electrode Materials ◽

Electrochemical Impedance ◽

Electrochemical Analysis ◽

Multiwalled Carbon Nanotube ◽

Spectroscopic Techniques ◽

Redox Potentials ◽

Multiwalled Carbon ◽

Iron Manganese

In this work, the effect of carbon on the electrochemical properties of multiwalled carbon nanotube (MWCNT) functionalized lithium iron manganese phosphate was studied. In an attempt to provide insight into the structural and electronic properties of optimized electrode materials, a systematic study based on a combination of structural and spectroscopic techniques was conducted. The phosphor-olivine LiFe0.5Mn0.5PO4 was synthesized via a simple microwave synthesis using LiFePO4 and LiMnPO4 as precursors. Cyclic voltammetry was used to evaluate the electrochemical parameters (electron transfer and ionic diffusivity) of the LiFe0.5Mn0.5PO4 redox couples. The redox potentials show two separate distinct redox peaks that correspond to Mn2+/Mn3+ (4.1 V vs Li/Li+) and Fe2+/Fe3+ (3.5 V vs Li/Li+) due to interaction arrangement of Fe-O-Mn in the olivine lattice. The electrochemical impedance spectroscopy (EIS) results showed LiFe0.5Mn0.5PO4-MWCNTs have high conductivity with reduced charge resistance. This result demonstrates that MWCNTs stimulate faster electron transfer and stability for the LiFe0.5Mn0.5PO4 framework, which demonstrates to be favorable as a host material for Li+ ions.

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Reduced Graphene Oxide/Multiwalled Carbon Nanotube Composite Decorated with Fe3O4 Magnetic Nanoparticles for Electrochemical Determination of Hydrazine in Environmental Water

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17379 ◽

2020 ◽

Vol 20 (5) ◽

pp. 3148-3156 ◽

Cited By ~ 2

Author(s):

S. Nehru ◽

Subramanian Sakthinathan ◽

P. Tamizhdurai ◽

Te-Wei Chiu ◽

K. Shanthi

Keyword(s):

Graphene Oxide ◽

Carbon Nanotube ◽

Magnetic Nanoparticles ◽

Reduced Graphene Oxide ◽

Electrochemical Impedance ◽

Limit Of Detection ◽

High Sensitivity ◽

Multiwalled Carbon Nanotube ◽

Multiwalled Carbon ◽

Reduced Graphene

In the present work, a reduced graphene oxide and multiwalled carbon nanotube (RGO/MWCNTFe3O4) composite decorated with Fe3O4 magnetic nanoparticles was prepared as an electrochemical sensor. The surface morphology of the prepared composite was identified by scanning electron microscopy and X-ray diffraction. The electrochemical properties of the GCE/RGO/MWCNT-Fe3O4 electrode were investigated by electrochemical impedance spectroscopy, cyclic voltammetry and amperometry. The GCE/RGO/MWCNT-Fe3O4 electrode exhibited higher electrocatalytic performance towards the oxidation of hydrazine. In the optimal conditions, the GCE/RGO/MWCNT-Fe3O4 electrode showed a wide linear range (0.15–220 μM), low limit of detection (LOD) (0.75 μM), and high sensitivity (2.868 μA μM−1 cm−2). The prepared GCE/RGO/MWCNT-Fe3O4 electrode also had excellent repeatability, selectivity, and reproducibility. The practical application of the electrode was confirmed with various spiked water samples and demonstrated acceptable recovery.

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Preparation of TiO2/Multiwalled Carbon Nanotube Composites and Their Applications in Photocatalytic Reduction of Cr(VI) Study

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.242 ◽

2008 ◽

Vol 8 (11) ◽

pp. 5624-5631 ◽

Cited By ~ 24

Author(s):

Xiaoli Tan ◽

Ming Fang ◽

Xiangke Wang

Keyword(s):

Carbon Nanotube ◽

Photoelectron Spectroscopy ◽

Ternary Systems ◽

Photocatalytic Reduction ◽

Multiwalled Carbon Nanotube ◽

X Ray Diffraction ◽

Multiwalled Carbon ◽

X Ray ◽

Nanotube Composites ◽

A Minor

The TiO2/multiwalled carbon nanotube (MWCNT) composites were prepared by hydrothermal deposition. Batch experiments were carried out to study the removal of Cr(VI) from aqueous solution to TiO2, MWCNTs and TiO2/MWCNTs. Scanning electron microscopy and X-ray diffraction were utilized to characterize the prepared TiO2/MWCNT composites. The introduction of MWCNTs onto TiO2 catalyst led to a remarkable increase of Cr(VI) removal through adsorption and photocatalytic reduction under ultraviolet irradiation. Results of X-ray photoelectron spectroscopy analysis of chromium species adsorbed on TiO2/MWCNTs phase revealed that the removal mechanism of Cr(VI) by TiO2/MWCNTs under UV-irradiation was the reduction of Cr(VI) into Cr(III). The adsorption and photocatalytic activity of Cr(VI) decreased with increasing in pH, and was not affected by the concentration of sulphate obviously. In the ternary systems humic acid (HA)/fulvic acid (FA)-Cr(VI)-TiO2/MWCNTs, the increasing of FA/HA concentration did not cause any drastic changes in the adsorption capacity in terms of Cr(VI) concentration in the dark, but a minor increasing trend for the photocatalytic reduction of Cr(VI). The presence of humic substances enhanced the photocatalytic reduction and adsorption of Cr(III) to TiO2/MWCNTs.

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Highly Sensitive Choline Oxidase Enzyme Inhibition Biosensor for Lead Ions Based on Multiwalled Carbon Nanotube Modified Glassy Carbon Electrodes

Electroanalysis ◽

10.1002/elan.201700111 ◽

2017 ◽

Vol 29 (7) ◽

pp. 1741-1748 ◽

Cited By ~ 6

Author(s):

Hend Samy Magar ◽

Mariana Emilia Ghica ◽

Mohammed Nooredeen Abbas ◽

Christopher M. A. Brett

Keyword(s):

Carbon Nanotube ◽

Enzyme Inhibition ◽

Glassy Carbon ◽

Choline Oxidase ◽

Multiwalled Carbon Nanotube ◽

Carbon Electrodes ◽

Multiwalled Carbon ◽

Glassy Carbon Electrodes ◽

Highly Sensitive ◽

Oxidase Enzyme

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Characterizing the Dopant Behavior of Functionalized Carbon Nanotubes in Conducting Polymers

MRS Proceedings ◽

10.1557/proc-788-l12.11 ◽

2003 ◽

Vol 788 ◽

Author(s):

Mark Hughe ◽

Graeme A. Snook ◽

George Z. Chen ◽

Milo S. P. Shaffer ◽

Derek J. Fray ◽

...

Keyword(s):

Carbon Nanotube ◽

Conducting Polymers ◽

Conducting Polymer ◽

Electrochemical Impedance ◽

Electrochemical Polymerization ◽

Polymer Chains ◽

Great Promise ◽

Multiwalled Carbon ◽

New Class ◽

Conducting Polymer Composites

ABSTRACTThe electrochemical polymerization of conducting polymers, such as polypyrrole, generally requires the incorporation of an anionic dopant to balance the positive charge on the oxidized conducting polymer chains. The susceptibility of multiwalled carbon nanotube (MWNT) surfaces to functionalization makes them exciting candidates for a new class of dopant for conducting polymers. In this work, the doping of polypyrrole with functionalized MWNTs is investigated using a combination of electrochemical impedance spectroscopy, scanning electron microscopy, and quartz crystal microbalance work. The findings described here are particularly relevant in light of recent reports indicating that carbon nanotube-conducting polymer composites hold great promise for use in electrochemical capacitors, also known as supercapacitors [1,2].

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X-RAY PHOTOELECTRON SPECTROSCOPY AND SCANNING ELECTROCHEMICAL MICROSCOPY STUDIES OF BRANCHED MULTIWALLED CARBON NANOTUBE PAPER MODIFIED BY ELECTROCHEMICAL GRAFTING AND CLICK CHEMISTRY

International Journal of Nanoscience ◽

10.1142/s0219581x13500178 ◽

2013 ◽

Vol 12 (03) ◽

pp. 1350017 ◽

Cited By ~ 1

Author(s):

MEGAN COATES ◽

TEBELLO NYOKONG

Keyword(s):

Carbon Nanotube ◽

Click Chemistry ◽

Photoelectron Spectroscopy ◽

Scanning Electrochemical Microscopy ◽

Multiwalled Carbon Nanotube ◽

Subsequent Reaction ◽

Multiwalled Carbon ◽

X Ray ◽

Walled Carbon Nanotubes ◽

Electrochemical Microscopy

Modification of nanomaterials through electrochemical grafting is a useful approach to introduce linking groups on to the surface of these structures. This work shows the possibility of applying electrochemical grafting to branched multiwalled carbon nanotube paper with an electrical resistance of 0.1 ohm-cm, and subsequent reaction of the grafted 4-azidobenzenediazonium with ethynylferrocene through the Sharpless click chemistry reaction. A comparison is made between this paper electrode and adsorbed single-walled carbon nanotubes on a glassy carbon electrode, with electrochemistry, X-ray photoelectron spectroscopy and scanning electrochemical microscopy used for characterization.

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