Electrochemical Deoxyribonucleic Acid Biosensor Based on Multiwalled Carbon Nanotubes/Ag-TiO2 Composite Film for Label-Free Phosphinothricin Acetyltransferase Gene Detection by Electrochemical Impedance Spectroscopy

The low dielectric constant of the nonpolar polymer poly(1-butene) (PB-1) limits its application as a diaphragm element in energy storage capacitors. In this work, Ba(Zr0.2Ti0.8)O3-coated multiwalled carbon nanotubes (BZT@MWCNTs) were first prepared by using the sol–gel hydrothermal method and then modified with polydopamine (PDA) via noncovalent polymerization. Finally, PB-1 matrix composite films filled with PDA-modified BZT@MWCNTs nanoparticles were fabricated through a solution-casting method. Results indicated that the PDA-modified BZT@MWCNTs had good dispersion and binding force in the PB-1 matrix. These characteristics improved the dielectric and energy storage performances of the films. Specifically, the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film exhibited the best dielectric performance. At 1 kHz, the dielectric constant of this film was 25.43, which was 12.7 times that of pure PB-1 films. Moreover, its dielectric loss was 0.0077. Furthermore, under the weak electric field of 210 MV·m−1, the highest energy density of the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film was 4.57 J·cm−3, which was over 3.5 times that of PB-1 film (≈1.3 J·cm−3 at 388 MV·m−1).

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Amperometric creatinine biosensor based on covalently coimmobilized enzymes onto carboxylated multiwalled carbon nanotubes/polyaniline composite film

Analytical Biochemistry ◽

10.1016/j.ab.2011.07.032 ◽

2011 ◽

Vol 419 (2) ◽

pp. 277-283 ◽

Cited By ~ 62

Author(s):

Sandeep Yadav ◽

Ashok Kumar ◽

C.S. Pundir

Keyword(s):

Carbon Nanotubes ◽

Composite Film ◽

Multiwalled Carbon Nanotubes ◽

Multiwalled Carbon

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Label-free analysis of water-polluting parasite by electrochemical impedance spectroscopy

Biosensors and Bioelectronics ◽

10.1016/j.bios.2009.09.039 ◽

2010 ◽

Vol 25 (5) ◽

pp. 1122-1129 ◽

Cited By ~ 28

Author(s):

T. Houssin ◽

J. Follet ◽

A. Follet ◽

E. Dei-Cas ◽

V. Senez

Keyword(s):

Electrochemical Impedance Spectroscopy ◽

Impedance Spectroscopy ◽

Electrochemical Impedance ◽

Label Free

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UNUSUAL ELECTROCHEMICAL RESPONSE OF ELECTROCHEMICAL ETCHING ON MULTIWALLED CARBON NANOTUBES

NANO ◽

10.1142/s1793292008001386 ◽

2008 ◽

Vol 03 (06) ◽

pp. 461-467 ◽

Cited By ~ 2

Author(s):

JIAN-SHAN YE ◽

GUANGQUAN MO ◽

WEI DE ZHANG ◽

XIAO LIU ◽

FWU-SHAN SHEU

Keyword(s):

Carbon Nanotubes ◽

Multiwalled Carbon Nanotubes ◽

Electrochemical Impedance ◽

Electrochemical Etching ◽

Current Response ◽

Multiwalled Carbon ◽

Transmission Electron ◽

Oxidation Of Glucose ◽

Total Disappearance ◽

Electrocatalytic Effects

Multiwalled carbon nanotubes (MWNTs) can be etched at potentials more positive than 1.7 V versus Ag / AgCl (3 M KCl ) in 0.2 M HNO 3. The electrochemically etched MWNTs show an increase in electrochemical impedance and sluggish electron transfer kinetics, and lose the electrocatalytic effects toward the oxidation of glucose, H 2 O 2, uric acid (UA) and L-ascorbic acid (L-AA). Transmission electron microscope (TEM) images reveal that the nanotube tips are cut off by electrochemical oxidation. This may lead to the degradation of electrocatalytic ability in the MWNTs. Furthermore, the current response after different electrochemically etched cycles shows that the electrocatalytic ability of the MWNTs toward different molecules can be tuned by etched cycles. For example, five etched cycles leads to the total disappearance of the oxidative response to L-AA, with the remaining over 50% of the UA current response in the L-AA and UA mixture. Thus, electrochemical etching is a simple yet novel way to tune the electrocatalytic reactivity and improve the selectivity of the MWNTs.

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