An Amperometric Immunosensor for α-Fetoprotein Based on Antibody Coated Nano ZrO2-Au-Poly Lysine Composite Membrane Modified Electrode

2011 ◽  
Vol 343-344 ◽  
pp. 490-496 ◽  
Author(s):  
Yuan Zhao Wu ◽  
Fu Tao Hu ◽  
Ning Gan ◽  
Jian Guo Hou ◽  
Tian Hua Li ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Composite Membrane ◽  
Electrochemical Impedance ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
Differential Pulse ◽  
Phenoxyacetic Acid ◽  
Serum Samples ◽  
Amperometric Immunosensor ◽  
Sensitivity And Selectivity

One novel amperometric immunosensor for α-fetop- rotein was fabricated which was modified by antibody immobilized on nano ZrO2-Au-polyLysine composite membrane. Firstly, the deoxyribonucleic acid – phenoxyacetic acid isoniazid- Schiff base Co(II) complex (DNA-CoL) mixture film was casted on surface of multi carbon nanotubes(MWCNTs) modified glassy carbon electrode(GCE/CNTs/DNA-CoL). Then the composite nanoparticles (ZrO2-Au-pLL) was employed to immobilize the antibody of α-fetoprotein(AFP) to produce the probes(ZrO2-Au-pLL-anti AFP) for AFP. Finally the probes were modified on GCE/CNTs/DNA-CoL through the specific connection between DNA and ZrO2 to form a novel nanocomposite membrane immunosensor for AFP(GCE/CNTs/ DNA-CoL/ZrO2-Au–pLL-anti AFP). The function of immunosensor was investigated by scanning electron microscopy (SEM), cyclic voltammetry(CV), differential pulse voltammety (DPV) and electrochemical impedance spectroscopy experiment (EIS). The results indicated that combining the advantages of the MWNTs-DNA material and ZrO2-Au-pLL-anti AFP nano probes, the immunosensor with excellent sensitivity and selectivity to AFP was prepared successfully. The modified electrode was sensitive to AFP with a linear relationship between 0.05 and 10 ng · mL−1 and a correl- ation coefficient of 0.9905. The detection limit at a signal to noise ratio of 3 was 0.01 ng·mL−1 under the optimal conditions. The described immunosensor preparation and immunoassay methods offer promise for simple and cost-effective analysis of AFP in serum samples.

Reagentless, Electrochemical Aptasensor for Lead (II) Detection

2017 ◽  
Vol 20 (1) ◽  
pp. 001-005 ◽  
Author(s):  
Yan Lin ◽  
Lin Cheng ◽  
Guo Bing Wei ◽  
Ling Ling He ◽  
Cha Dan Chen ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Chinese Herb ◽  
Amperometric Detection ◽  
Differential Pulse ◽  
Random Coil ◽  
Lead Ion ◽  
Sensitivity And Selectivity ◽  
One Step ◽  
Novel Strategy

A novel strategy for selective and sensitive amperometric detection of lead ion (Pb2+) was proposed based on target-inducedconformational switch. The ferrocene-labeled aptamer thiol was self-assembled through S-Au bonding on a gold electrode surface and thesurface was blocked with 2-mercaptoethanol to form a mixed monolayer. The aptamer-modified electrode was characterized electrochemicallyby differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The modified electrode showed a voltammetricsignal due to a one-step redox reaction of the surface-confined ferrocenyl moiety of the aptamer immobilized on the electrodesurface in 20mM Tris–HCl buffers buffer of pH 7.4. The “signal-on” upon Pb2+ association could be attributed to a change in conformationfrom random coil-like configuration on the probe-modified film to the quadruplex structure. The fabricated biosensor showed alinear response to the logarithm of Pb2+ concentration over the range of 5.0×10-10 M to 1.0×10-7 M with a detection limit of 1.2×10-10 M.In addition, this strategy afforded an exquisite selectivity for Pb2+ against other metal ions. The excellent sensitivity and selectivity showgood potential for Pb2+ detection in real Chinese herb samples.

scholarly journals Highly Sensitive Detection of Dopamine at Ionic Liquid Functionalized RGO/ZIF-8 Nanocomposite-Modified Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Lei Cheng ◽  
Youjun Fan ◽  
Xingcan Shen ◽  
Hong Liang
Keyword(s):  
Ionic Liquid ◽  
Modified Electrode ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Differential Pulse ◽  
Zeolitic Imidazolate Framework ◽  
Response Range ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

A hybrid and hierarchical nanocomposite was successfully prepared by the growth of zeolitic imidazolate framework-8 (ZIF-8) on the template of ionic liquid (IL, [Bmim][BF4]) functionalized reduced graphene oxide (IL-RGO). The structure and morphology of the IL-RGO/ZIF-8 nanocomposite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and Raman spectroscopy. The results showed that RGO sheets were refrained from restacking by IL, and ZIF-8 nanoparticles grew well on the surface of IL-RGO. Owing to the synergistic effect from large surface area and excellent electrocatalytic activity of ZIF-8 and great electrical conductivity of IL-RGO, a highly sensitive sensor for dopamine (DA) can be obtained. IL-RGO/ZIF-8-modified electrode exhibits good electrocatalytic activity and electroconductive properties towards DA which were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Compared with bare or IL-RGO-modified electrodes, the IL-RGO/ZIF-8-modified electrode effectively depressed the oxidation overpotential of DA. The linear response range of DA was from 1.0×10−7 to 1.0×10−4 mol/L with a low detection of limit 3.5×10−8 mol/L. In addition, the sensor was shown to provide satisfactory stability for the determination of DA.

scholarly journals Novel Electrochemical Sensor Fabricated for Individual and Simultaneous Ultrasensitive Determination of Olaquindox and Carbadox Based on MWCNT-OH/CMK-8 Hybrid Nanocomposite Film

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3041 ◽  
Author(s):  
Yanqing Liu ◽  
Gengxin Hu ◽  
Hongwu Wang ◽  
Su Yao ◽  
Yinjian Ye
Keyword(s):  
Electrochemical Sensor ◽  
Simultaneous Determination ◽  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Differential Pulse ◽  
Hybrid Nanocomposite ◽  
Experimental Conditions ◽  
Linear Relationships

A hybrid nanocomposite consisting of hydroxylated multi-walled carbon nanotubes (MWCNTs−OH) and cube mesoporous carbon (CMK−8) was applied in this study to construct an MWCNT−OH/CMK−8/gold electrode (GE) electrochemical sensor and simultaneously perform the electro-reduction of olaquindox (OLA) and carbadox (CBX). The respective peak currents of CBX and OLA on the modified electrode increased by 720- and 595-fold relative to the peak current of GE. The performances of the modified electrode were investigated with electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Then, the modified electrodes were used for the individual and simultaneous determination of OLA and CBX. The fabricated sensor demonstrated a linear response at 0.2–500 nmol/L in optimum experimental conditions, and the detection limits were 104.1 and 62.9 pmol/L for the simultaneous determination of OLA and CBX, respectively. As for individual determination, wide linear relationships were obtained for the detected OLA with levels of 0.05–500 nmol/L with LOD of 20.7 pmol/L and the detected CBX with levels of 0.10–500 nmol/L with LOD of 50.2 pmol/L. The fabricated sensor was successfully used in the independent and simultaneous determination of OLA and CBX in spiked pork samples.

Application of cetyltrimethylammonium bromide – graphene modified electrode for sensitive determination of caffeine

2011 ◽  
Vol 89 (6) ◽  
pp. 697-702 ◽  
Author(s):  
Jun-Yong Sun ◽  
Ke-Jing Huang ◽  
Shuai-Yun Wei ◽  
Zhi-Wei Wu
Keyword(s):  
Modified Electrode ◽  
Cetyltrimethylammonium Bromide ◽  
Electrochemical Sensors ◽  
Signal To Noise Ratio ◽  
Soft Drink ◽  
Differential Pulse ◽  
Experimental Conditions ◽  
Long Term Stability ◽  
Good Electrocatalytic Activity ◽  
Sensitive Determination

An electrochemical sensor based on a cationic surfactant cetyltrimethylammonium bromide (CTAB) – dispersed graphene (Gr) system for sensitive detection of caffeine is presented. The electrochemical behavior of caffeine on the modified glassy carbon electrode was investigated by cyclic voltammetry and differential pulse voltammetry. The results showed that the modified electrode exhibited good electrocatalytic activity to the oxidation of caffeine. Under the optimized experimental conditions, caffeine was detected in the concentration range from 0.3 to 100 µmol L–1 with a detection limit of 91 nmol L–1 at a signal-to-noise ratio = 3. The biosensor exhibited some advantages over other electrochemical sensors, such as long-term stability, satisfactory recovery (98.1%−102.3%), and good reproducibility (RSD = 5.1%). The practical application of the developed method was verified in soft-drink sample analysis.

scholarly journals Novel CNT Supported Molybdenum Catalyst for Detection of L-Cysteine in Its Natural Environment

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1561
Author(s):  
Kadir Selçuk ◽  
Hilal Kivrak ◽  
Nahit Aktaş
Keyword(s):  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Signal To Noise Ratio ◽  
Differential Pulse ◽  
Current Sensitivity ◽  
X Ray ◽  
Temperature Programmed Oxidation ◽  
Voltammetric Techniques ◽  
Sodium Borohydride Reduction ◽  
Temperature Programmed

In this study, novel carbon nanotube-supported Mo (Mo/CNT) catalysts were prepared with the sodium borohydride reduction method for the detection of L-cysteine (L-Cys, L-C). Mo/CNT catalysts were characterized with scanning electron microscopy with elemental dispersion X-ray (EDX-SEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectrometry (UV-vis), temperature-programmed reduction (TPR), temperature programmed oxidation (TPO), and temperature-programmed desorption (TPD) techniques. The results of these advanced surface characterization techniques revealed that the catalysts were prepared successfully. Electrochemical measurements were employed to construct a voltammetric L-C sensor based on Mo/CNT catalyst by voltammetric techniques such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Further measurements were carried out with electrochemical impedance spectroscopy (EIS). Mo/CNT/GCE exhibited excellent performance for L-C detection with a linear response in the range of 0–150 µM, with a current sensitivity of 200 mA/μM cm2 (0.0142 μA/μM), the lowest detection limit of 0.25 μM, and signal-to-noise ratio (S/N = 3). Interference studies showed that the Mo/CNT/GCE electrode was not affected by D-glucose, uric acid, L-tyrosine, and L-trytophane, commonly interfering organic structures. Natural sample analysis was also accomplished with acetyl L-C. Mo/CNT catalyst is a promising material as a sensor for L-C detection.

scholarly journals Carbon nanotube-ionic liquid nanocomposite modified carbon-ceramic electrode for determination of dopamine in real samples

2013 ◽  
Vol 11 (7) ◽  
pp. 1172-1186 ◽  
Author(s):  
Mir Majidi ◽  
Reza Baj ◽  
Abdolhossein Naseri
Keyword(s):  
Ionic Liquid ◽  
Carbon Nanotube ◽  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Differential Pulse ◽  
Selective Determination ◽  
Carbon Ceramic Electrode ◽  
Electro Oxidation ◽  
Carbon Ceramic

AbstractRoom temperature 1-butyl-3-methylimidazolium tetraflouroborate ([BMIM][BF4]) ionic liquid was employed for dispersion of multi walled carbon nanotubes (MWCNTs) and the formation of nanocomposite on the surface of a carbon-ceramic electrode. The surface of the modified electrode was characterized using scanning electron microscopy and electrochemical impedance spectroscopy. The modified electrode exhibited excellent electrochemical activity to oxidation of dopamine (DA); whereas electro oxidation of ascorbic acid (AA) was not seen and electro oxidation of uric acid (UA) appeared at a more positive potential than DA. The multi walled carbon nanotube-ionic liquid nanocomposite modified carbon-ceramic electrode was used for the selective determination of DA in the presence of high levels of AA and UA using differential pulse voltammetry. The calibration curve for DA was linear in the range of 3.00 to 130 µM with the detection limit (S/N=3) of 0.87 µM. The present electrode was successfully applied to the determination of DA in some commercial pharmaceutical samples and human blood serum.

A novel approach to design electrochemical aptamer-based biosensor for ultrasensitive detecting of zearalenone as a prevalent estrogenic mycotoxin

2021 ◽  
Vol 28 ◽  
Author(s):  
Shokoufeh Hassani ◽  
Armin Salek Maghsoudi ◽  
Milad Rezaei Akmal ◽  
Shahram Shoeibi ◽  
Fatemeh Ghadipasha ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Fusarium Species ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Differential Pulse ◽  
Electrode Position ◽  
Novel Approach ◽  
Modified Surface

Background: Zearalenone is a well-known estrogenic mycotoxin produced by Fusarium species, a serious threat to the agricultural and food industries worldwide. Zearalenone, with its known metabolites, are biomarkers of exposure to certain fungi, primarily through food. It has considerable toxic effects on biological systems due to its carcinogenicity, mutagenicity, renal toxicity, teratogenicity, and immunotoxicity. Introduction: This study aims to design a simple, quick, precise, and cost-effective method on a biosensor platform to evaluate the low levels of this toxin in foodstuffs and agricultural products. Methods: An aptamer-based electrochemical biosensor was introduced that utilizes screen-printed gold electrodes instead of conventional electrodes. The electrode position process was employed to develop a gold nanoparticle-modified surface to enhance the electroactive surface area. Thiolated aptamers were immobilized on the surface of gold nanoparticles, and subsequently, the blocker and analyte were added to the modified surface. In the presence of a redox probe, electrochemical characterization of differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy were used to investigate the various stages of aptasensor fabrication. Results: The proposed aptasensor for zearalenone concentration had a wide linear dynamic range covering the 0.5 pg/mL to 100 ng/mL with a 0.14 pg/mL detection limit. Moreover, this aptasensor had high specificity so that a non-specific analyte cannot negatively affect the selectivity of the aptasensor. Conclusion: Overall, due to its simple design, high sensitivity, and fast performance, this aptasensor showed a high potential for assessing zearalenone in real samples, providing a clear perspective for designing a portable and cost-effective device.

Electrochemical Reduction and Detection of Nitrobenzene Based on Porphyrin Composite-modified Glassy Carbon Electrode

2014 ◽  
Vol 67 (5) ◽  
pp. 796 ◽  
Author(s):  
Zhonghua Xue ◽  
Huan Lian ◽  
Chenxian Hu ◽  
Yanjun Feng ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Signal To Noise Ratio ◽  
Differential Pulse ◽  
Field Analysis ◽  
Carbon Electrodes ◽  
Solution Ph ◽  
Sensitive Material ◽  
Glassy Carbon Electrodes ◽  
Ordered Mesoporous

An electrocatalytic platform and electrochemical sensor for nitrobenzene using tetra(4-methoxyphenyl) porphyrin-functionalized N-doped ordered mesoporous carbon (TMPP/N-OMC) as sensitive material is reported. Glassy carbon electrodes modified with TMPP/N-OMC were characterized by scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The electrode shows high electrocatalytic activity towards the reduction of nitrobenzene in sodium chloride solution (pH 7.00). Electrocatalytic reduction currents of nitrobenzene were found to be linearly related to concentration over the range 0.528 to 132.00 μM with a correlation coefficient of 0.9971 using a differential pulse voltammogram method. The detection limits were determined as 0.2162 μM at a signal-to-noise ratio of 3. The results show TMPP/N-OMC-modified glassy carbon electrodes open new opportunities for fast, simple, and sensitive field analysis of nitrobenzene.

scholarly journals Sensor Based on a Poly[2-(Dimethylamino)ethyl Methacrylate-Co-Styrene], Gold Nanoparticles, and Methylene Blue-Modified Glassy Carbon Electrode for Melamine Detection

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2850
Author(s):  
Fairouz Aberkane ◽  
Imene Abdou ◽  
Nadia Zine ◽  
Nicole Jaffrezic-Renault ◽  
Abdelhamid Elaissari ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Gold Nanoparticles ◽  
Impedance Spectroscopy ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Detection Range

Melamine has been used as a non-protein nitrogenous additive in food products to artificially increase the apparent “false” protein content. Melamine is known as a dangerous and poisonous substance for human health and it causes diverse diseases. An electrochemical sensor for melamine detection has been developed by modification of a glassy carbon electrode using copolymer poly[DMAEMA-co-styrene], gold nanoparticles, and methylene blue. The characterization of the modified electrode was conducted using several analysis techniques including cyclic voltammetry (CV), differential pulse voltammetry (DPV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The electrochemical detection of melamine was performed by impedance spectroscopy. Obtained results revealed that the developed sensor has a large detection range from 5.0 × 10−13 to 3.8 × 10−8 M with a low detection limit of 1.8 × 10−12 M (at S/N = 3). Various interfering species such as phenol, hydroquinone, and bisphenol A have been used and their behavior on modified electrode has been studied.

scholarly journals Cu-Doped ZnO Nanoparticles for Non-Enzymatic Glucose Sensing

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 929
Author(s):  
Amira Mahmoud ◽  
Mosaab Echabaane ◽  
Karim Omri ◽  
Julien Boudon ◽  
Lucien Saviot ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Chemical Properties ◽  
Differential Pulse ◽  
Glucose Sensing ◽  
Serum Samples ◽  
Experimental Conditions ◽  
Active Electrode ◽  
Transmission Electron

Copper-doped zinc oxide nanoparticles (NPs) CuxZn1−xO (x = 0, 0.01, 0.02, 0.03, and 0.04) were synthesized via a sol-gel process and used as an active electrode material to fabricate a non-enzymatic electrochemical sensor for the detection of glucose. Their structure, composition, and chemical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) and Raman spectroscopies, and zeta potential measurements. The electrochemical characterization of the sensors was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Cu doping was shown to improve the electrocatalytic activity for the oxidation of glucose, which resulted from the accelerated electron transfer and greatly improved electrochemical conductivity. The experimental conditions for the detection of glucose were optimized: a linear dependence between the glucose concentration and current intensity was established in the range from 1 nM to 100 μM with a limit of detection of 0.7 nM. The proposed sensor exhibited high selectivity for glucose in the presence of various interfering species. The developed sensor was also successfully tested for the detection of glucose in human serum samples.

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