scholarly journals A label-free biosensor based on graphene and reduced graphene oxide dual-layer for electrochemical determination of beta-amyloid biomarkers

2020 ◽  
Vol 187 (5) ◽  
Author(s):  
Jagriti Sethi ◽  
Michiel Van Bulck ◽  
Ahmed Suhail ◽  
Mina Safarzadeh ◽  
Ana Perez-Castillo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Label Free ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

AbstractA label-free biosensor is developed for the determination of plasma-based Aβ1–42 biomarker in Alzheimer’s disease (AD). The platform is based on highly conductive dual-layer of graphene and electrochemically reduced graphene oxide (rGO). The modification of dual-layer with 1-pyrenebutyric acid N-hydroxysuccinimide ester (Pyr-NHS) is achieved to facilitate immobilization of H31L21 antibody. The effect of these modifications were studied with morphological, spectral and electrochemical techniques. The response of the biosensor was evaluated using differential pulse voltammetry (DPV). The data was acquired at a working potential of ~ 180 mV and a scan rate of 50 mV s−1. A low limit of detection (LOD) of 2.398 pM is achieved over a wide linear range from 11 pM to 55 nM. The biosensor exhibits excellent specificity over Aβ1–40 and ApoE ε4 interfering species. Thus, it provides a viable tool for electrochemical determination of Aβ1–42. Spiked human and mice plasmas were used for the successful validation of the sensing platform in bio-fluidic samples. The results obtained from mice plasma analysis concurred with the immunohistochemistry (IHC) and magnetic resonance imaging (MRI) data obtained from brain analysis.

scholarly journals Label-Free DNA Biosensor Using Modified Reduced Graphene Oxide Platform as a DNA Methylation Assay

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4936 ◽  
Author(s):  
Eliska Sedlackova ◽  
Zuzana Bytesnikova ◽  
Eliska Birgusova ◽  
Pavel Svec ◽  
Amir M. Ashrafi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Clinical Diagnostics ◽  
Label Free ◽  
Free Dna ◽  
Methylation Assay ◽  
Reduced Graphene

This work reports the use of modified reduced graphene oxide (rGO) as a platform for a label-free DNA-based electrochemical biosensor as a possible diagnostic tool for a DNA methylation assay. The biosensor sensitivity was enhanced by variously modified rGO. The rGO decorated with three nanoparticles (NPs)—gold (AuNPs), silver (AgNPs), and copper (CuNPs)—was implemented to increase the electrode surface area. Subsequently, the thiolated DNA probe (single-stranded DNA, ssDNA−1) was hybridized with the target DNA sequence (ssDNA-2). After the hybridization, the double-stranded DNA (dsDNA) was methylated by M.SssI methyltransferase (MTase) and then digested via a HpaII endonuclease specific site sequence of CpG (5′-CCGG-3′) islands. For monitoring the MTase activity, differential pulse voltammetry (DPV) was used, whereas the best results were obtained by rGO-AuNPs. This assay is rapid, cost-effective, sensitive, selective, highly specific, and displays a low limit of detection (LOD) of 0.06 U·mL−1. Lastly, this study was enriched with the real serum sample, where a 0.19 U·mL−1 LOD was achieved. Moreover, the developed biosensor offers excellent potential in future applications in clinical diagnostics, as this approach can be used in the design of other biosensors.

scholarly journals Electrochemical Determination of Paracetamol Using Fe3O4/Reduced Graphene-Oxide-Based Electrode

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Nguyen Thi Anh Thu ◽  
Hoang Van Duc ◽  
Nguyen Hai Phong ◽  
Nguyen Duc Cuong ◽  
Nguyen Thi Vuong Hoan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Anodic Stripping Voltammetry ◽  
Electrochemical Determination ◽  
Spherical Particles ◽  
Current Response ◽  
X Ray ◽  
Reduced Graphene

The synthesis of magnetic iron oxide/reduced graphene oxide (Fe3O4/rGO) and its application to the electrochemical determination of paracetamol using Fe3O4/rGO modified electrode were demonstrated. The obtained materials were characterized by means of X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), and magnetic measurement. The results showed that Fe3O4/rGO composite exhibited high specific surface area, and its morphology consists of very fine spherical particles of Fe3O4 in nanoscales. Fe3O4/rGO was used as an electrode modifier for the determination of paracetamol by differential pulse-anodic stripping voltammetry (DP-ASV). The preparation of Fe3O4/rGO-based electrode and some factors affecting voltammetric responses were investigated. The results showed that Fe3O4/rGO is a potential electrode modifier for paracetamol detection by DP-ASV with a low limit of detection. The interfering effect of uric acid, ascorbic acid, and dopamine on the current response of paracetamol has been reported. The repeatability, reproducibility, linear range, and limit of detection were also addressed. The proposed method could be applied to the real samples with satisfactory results.

scholarly journals Simultaneous Voltammetric Determination of Ascorbic Acid, Paracetamol, and Caffeine Using Electrochemically Reduced Graphene-Oxide-Modified Electrode

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Nguyen Hai Phong ◽  
Tran Thanh Tam Toan ◽  
Mai Xuan Tinh ◽  
Tran Ngoc Tuyen ◽  
Tran Xuan Mau ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Anodic Stripping Voltammetry ◽  
Pharmaceutical Preparations ◽  
Differential Pulse ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

In the present paper, graphene oxide was directly electrodeposited by means of cyclic voltammetric techniques on the glassy-carbon electrode (GCE) to obtain a reduced graphene-oxide-modified electrode (ErGO/GCE). Cyclic voltammetry (CV) and differential pulse anodic stripping voltammetry (DP-ASV) had been utilized to study the electrochemical behavior of ErGO/GCE toward ascorbic acid (AA), paracetamol (PA), and caffeine (CA). Differential pulse voltammetry results show that AA, PA, and CA could be detected selectively and sensitively on ErGO/GCE with peak-to-peak separation of 312 mV and 756 mV for AA–PA and PA–CA, respectively. The factors affecting the voltammetric signals such as pH, scan rate, and interferents were addressed. The results reveal that the ErGO/GCE-modified electrode exhibits excellent electrochemical activity in the oxidation of PA, CA, and AA. The detection limits are 0.36 μM, 0.25 μM, and 0.23 μM for AA, PA and CA, respectively, suggesting that the ErGO/GCE can be utilized with high sensitivity and selectivity for the simultaneous determination of these compounds. Finally, the proposed method was successfully used to determine AA, PA, and CA in pharmaceutical preparations.

scholarly journals A Robust Electrochemical Sensor for Determination of ThiamethoxamBased on Electrochemical Reduced Graphene Oxide-Cationic Pillar[6]arene Composite Film

2021 ◽  
Author(s):  
Yanju Wu ◽  
Zikang Li ◽  
Dongyang Han ◽  
Qunpeng Duan ◽  
Fei Wang
Keyword(s):  
Graphene Oxide ◽  
Composite Film ◽  
Reduced Graphene Oxide ◽  
Differential Pulse ◽  
Potential Method ◽  
Electrochemical Sensing ◽  
Sensing Platform ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

Abstract On the surface of a glassy carbon electrode, electrochemically reduced graphene oxide-cationic pillar[6]arene (ErGO-CP6) composite film was constructed using a pulsed potential method. UV-vis spectra, SEM, Raman spectra and electrochemical experiments were applied to characterize the composite film. It was then used as a new electrochemical sensing platform for determination of thiamethoxam. Due to the synergistic effect of ErGO and CP6, this composite film shows a higher sensitivity and better selectivity toward thiamethoxam than that of ErGO film. The linear range from 1.0 × 10-7 to 1.3 × 10-5 mol L-1 was obtained by differential pulse voltammetry. Meanwhile, the method was applied to cucumber and tomato samples in a recovery test. The recovery was between 92.0% and 98.7%, and the results are satisfactory. This study presents a promising electrochemical sensing platform for rapid and sensitive analysis of thiamethoxam.

scholarly journals Correction to: A label-free biosensor based on graphene and reduced graphene oxide dual-layer for electrochemical determination of beta-amyloid biomarkers

2020 ◽  
Vol 187 (6) ◽  
Author(s):  
Jagriti Sethi ◽  
Michiel Van Bulck ◽  
Ahmed Suhail ◽  
Mina Safarzadeh ◽  
Ana Perez-Castillo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Beta Amyloid ◽  
Electrochemical Determination ◽  
Label Free ◽  
Reduced Graphene

scholarly journals Simultaneous Determination of Uric Acid and Xanthine Using a Poly(Methylene Blue) and Electrochemically Reduced Graphene Oxide Composite Film Modified Electrode

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Gen Liu ◽  
Wei Ma ◽  
Yan Luo ◽  
Deng-ming Sun ◽  
Shuang Shao
Keyword(s):  
Methylene Blue ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Composite Film ◽  
Simultaneous Determination ◽  
Reduced Graphene Oxide ◽  
Modified Electrode ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

Poly(methylene blue) and electrochemically reduced graphene oxide composite film modified electrode (PMB-ERGO/GCE) was successfully fabricated by electropolymerization and was used for simultaneous determination of uric acid (UA) and xanthine (Xa). Based on the excellent electrocatalytic activity of PMB-ERGO/GCE, the electrochemical behaviors of UA and Xa were studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). Two anodic sensitive peaks at 0.630 V (versus Ag/AgCl) for UA and 1.006 V (versus Ag/AgCl) for Xa were given by CV in pH 3.0 phosphate buffer. The calibration curves for UA and Xa were obtained in the range of 8.00 × 10−8~4.00 × 10−4 M and 1.00 × 10−7~4.00 × 10−4 M, respectively, by SWV. The detection limits for UA and Xa were3.00×10-8 M and5.00×10-8 M, respectively. Finally, the proposed method was applied to simultaneously determine UA and Xa in human urine with good selectivity and high sensitivity.

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