scholarly journals Sequence-Independent DNA Adsorption on Few-Layered Oxygen-Functionalized Graphene Electrodes: An Electrochemical Study for Biosensing Application

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 273
Author(s):  
Narges Asefifeyzabadi ◽  
Torrey E. Holland ◽  
Poopalasingam Sivakumar ◽  
Saikat Talapatra ◽  
Ishani M. Senanayake ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Low Cost ◽  
Differential Pulse ◽  
Current Response ◽  
Functionalized Graphene ◽  
Label Free ◽  
Dna Adsorption ◽  
Redox Probe ◽  
Highly Sensitive ◽  
Electrochemical Charge Transfer

DNA is strongly adsorbed on oxidized graphene surfaces in the presence of divalent cations. Here, we studied the effect of DNA adsorption on electrochemical charge transfer at few-layered, oxygen-functionalized graphene (GOx) electrodes. DNA adsorption on the inkjet-printed GOx electrodes caused amplified current response from ferro/ferricyanide redox probe at concentration range 1 aM–10 nM in differential pulse voltammetry. We studied a number of variables that may affect the current response of the interface: sequence type, conformation, concentration, length, and ionic strength. Later, we showed a proof-of-concept DNA biosensing application, which is free from chemical immobilization of the probe and sensitive at attomolar concentration regime. We propose that GOx electrodes promise a low-cost solution to fabricate a highly sensitive platform for label-free and chemisorption-free DNA biosensing.

Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long
Keyword(s):  
Electrochemical Sensor ◽  
Molecular Imprinting ◽  
Neurological Disorders ◽  
Room Temperature ◽  
Low Cost ◽  
Differential Pulse ◽  
Current Response ◽  
Specific Selectivity ◽  
Pulse Voltammetry

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

scholarly journals A highly sensitive biosensor based on methacrylated graphene oxide-grafted polyaniline for ascorbic acid determination

2020 ◽  
Vol 9 (1) ◽  
pp. 760-767 ◽  
Author(s):  
Seyed Morteza Naghib ◽  
Farahnaz Behzad ◽  
Mehdi Rahmanian ◽  
Yasser Zare ◽  
Kyong Yop Rhee
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Current Response ◽  
Functionalized Graphene ◽  
Serum Samples ◽  
Promising Candidate ◽  
Graphene Nanocomposites ◽  
Selective Determination ◽  
Highly Sensitive

AbstractFunctionalized graphene-based nanocomposites have opened new windows to address some challenges for increasing the sensitivity, accuracy and functionality of biosensors. Polyaniline (PANI) is one of the most potentially promising and technologically important conducting polymers, which brings together the electrical features of metals with intriguing properties of plastics including facile processing and controllable chemical and physical properties. PANI/graphene nanocomposites have attracted intense interest in various fields due to unique physicochemical properties including high conductivity, facile preparation and intriguing redox behavior. In this article, a functionalized graphene-grafted nanostructured PANI nanocomposite was applied for determining the ascorbic acid (AA) level. A significant current response was observed after treating the electrode surface with methacrylated graphene oxide (MeGO)/PANI nanocomposite. The amperometric responses showed a robust linear range of 8–5,000 µM and detection limit of 2 µM (N = 5). Excellent sensor selectivity was demonstrated in the presence of electroactive components interfering species, commonly found in real serum samples. This sensor is a promising candidate for rapid and selective determination of AA.

scholarly journals Highly Sensitive Non-Enzymatic Detection of Glucose at MWCNT-CuBTC Composite Electrode

2020 ◽  
Vol 10 (23) ◽  
pp. 8419
Author(s):  
Adriana Remes ◽  
Florica Manea ◽  
Sorina Motoc (m. Ilies) ◽  
Anamaria Baciu ◽  
Elisabeta I. Szerb ◽  
...  
Keyword(s):  
Composite Electrode ◽  
Glucose Sensor ◽  
Low Cost ◽  
Multiwall Carbon Nanotubes ◽  
Linear Sweep Voltammetry ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Roll Mill ◽  
Highly Sensitive ◽  
Enzymatic Detection

A novel electrochemical glucose sensor was developed, based on a multiwall carbon nanotubes (MWCNTs)-copper-1,3,5-benzenetricarboxylic acid (CuBTC)-epoxy composite electrode, named MWCNT-CuBTC. The electrode nanocomposite was prepared by a two-roll mill procedure and characterized morphostructurally by scanning electron microscopy (SEM). The CuBTC formed defined crystals with a wide size distribution, which were well dispersed and embedded in the MWCNTs. Its electrical conductivity was determined by four-point probe contact (DC) conductivity measurements. The electroactive surface area, determined using cyclic voltammetry (CV), was found to be 6.9 times higher than the geometrical one. The results of the electrochemical measurements using CV, linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), chronoamperometry (CA) and multiple pulse amperometry (MPA) showed that the MWCNT-CuBTC composite electrode displayed high electrocatalytic activity toward the oxidation of glucose and, as a consequence, very high sensitivity. The best sensitivity of 14,949 µAmM−1cm−1 was reached using MPA at the potential value of 0.6 V/SCE, which was much higher in comparison with other copper-based electrodes reported in the literature. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of an effective glucose sensor.

scholarly journals Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

2019 ◽  
Vol 10 ◽  
pp. 2483-2496
Author(s):  
Jingran Zhang ◽  
Tianqi Jia ◽  
Yongda Yan ◽  
Li Wang ◽  
Peng Miao ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Enhancement Factor ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Production Method ◽  
Copper Surface ◽  
Sers Substrate ◽  
Label Free ◽  
Sers Substrates ◽  
Highly Sensitive

Nanostructures have been widely employed in surface-enhanced Raman scattering (SERS) substrates. Recently, in order to obtain a higher enhancement factor at a lower detection limit, hierarchical structures, including nanostructures and nanoparticles, appear to be viable SERS substrate candidates. Here we describe a novel method integrating the nanoindentation process and chemical redox reaction to machine a hierarchical SERS substrate. The micro/nanostructures are first formed on a Cu(110) plane and then Ag nanoparticles are generated on the structured copper surface. The effect of the indentation process parameters and the corrosion time in the AgNO3 solution on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multiple Ag nanoparticles on the surface of a plane and with multiple micro/nanostructures are studied with COMSOL software. The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor using malachite green molecules was found to reach 5.089 × 109, which demonstrates that the production method is a simple, reproducible and low-cost method for machining a highly sensitive, hierarchical SERS substrate.

An aptamer based voltammetric biosensor for endotoxins using a functionalized graphene and molybdenum disulfide composite as a new nanocarrier

The Analyst ◽  
2019 ◽  
Vol 144 (4) ◽  
pp. 1253-1259 ◽  
Author(s):  
Yonghua Yuan ◽  
Linlin Li ◽  
Min Zhao ◽  
Jing Zhou ◽  
Zhihui Chen ◽  
...  
Keyword(s):  
Molybdenum Disulfide ◽  
Functionalized Graphene ◽  
Label Free ◽  
Highly Sensitive

This work describes a label-free aptasensor for highly sensitive endotoxin detection using a functionalized graphene and molybdenum disulfide composite for amplification.

scholarly journals Highly Sensitive Electrochemical Aptasensor for Detecting the VEGF165 Tumor Marker with PANI/CNT Nanocomposites

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 114
Author(s):  
Yunjeong Park ◽  
Min-Sung Hong ◽  
Woo-Hyuk Lee ◽  
Jung-Gu Kim ◽  
Kyunghoon Kim
Keyword(s):  
Tumor Marker ◽  
Limit Of Detection ◽  
Biological Fluid ◽  
Low Cost ◽  
High Sensitivity ◽  
Label Free ◽  
Electrochemical Aptasensor ◽  
Promising Tool ◽  
Highly Sensitive ◽  
Endothelial Growth Factor

Sensing targeted tumor markers with high sensitivity provides vital information for the fast diagnosis and treatment of cancer patients. A vascular endothelial growth factor (VEGF165) have recently emerged as a promising biomarker of tumor cells. The electrochemical aptasensor is a promising tool for detecting VEGF165 because of its advantages such as a low cost and quantitative analysis. To produce a sensitive and stable sensor electrode, nanocomposites based on polyaniline (PANI) and carbon nanotube (CNT) have potential, as they provide for easy fabrication, simple synthesis, have a large surface area, and are suitable in biological environments. Here, a label-free electrochemical aptasensor based on nanocomposites of CNT and PANI was prepared for detecting VEGF165 as a tumor marker. The nanocomposite was assembled with immobilized VEGF165 aptamer as a highly sensitive VEGF165 sensor. It exhibited stable and wide linear detection ranges from 0.5 pg/mL to 1 μg/mL, with a limit of detection of 0.4 pg/mL because of the complementary effect of PANI/CNT. The fabricated aptasensor also exhibited good stability in biological conditions, selectivity, and reproducibility after several measurement times after the dissociation process. Thus, it could be applied for the non-invasive determination of VEGF, in biological fluid diagnosis kits, or in an aptamer-based biosensor platform in the near future.

scholarly journals Laser-Induced Graphene Electrodes Modified with a Molecularly Imprinted Polymer for Detection of Tetracycline in Milk and Meat

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 269
Author(s):  
Biresaw D. Abera ◽  
Inmaculada Ortiz-Gómez ◽  
Bajramshahe Shkodra ◽  
Francisco J. Romero ◽  
Giuseppe Cantarella ◽  
...  
Keyword(s):  
Molecularly Imprinted Polymer ◽  
Limit Of Detection ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
Animal Origin ◽  
Label Free ◽  
Imprinted Polymer ◽  
Meat Extract ◽  
Molecularly Imprinted

Tetracycline (TC) is a widely known antibiotic used worldwide to ‘’treat animals. Its residues in animal-origin foods cause adverse health effects to consumers. Low-cost and real-time measuring systems of TC in food samples are, therefore, extremely needed. In this work, a three-electrode sensitive and label-free sensor was developed to detect TC residues from milk and meat extract samples, using CO2 laser-induced graphene (LIG) electrodes modified with gold nanoparticles (AuNPs) and a molecularly imprinted polymer (MIP) used as a synthetic biorecognition element. LIG was patterned on a polyimide (PI) substrate, reaching a minimum sheet resistance (Rsh) of 17.27 ± 1.04 Ω/sq. The o-phenylenediamine (oPD) monomer and TC template were electropolymerized on the surface of the LIG working electrode to form the MIP. Surface morphology and electrochemical techniques were used to characterize the formation of LIG and to confirm each modification step. The sensitivity of the sensor was evaluated by differential pulse voltammetry (DPV), leading to a limit of detection (LOD) of 0.32 nM, 0.85 nM, and 0.80 nM in buffer, milk, and meat extract samples, respectively, with a working range of 5 nM to 500 nM and a linear response range between 10 nM to 300 nM. The sensor showed good LOD (0.32 nM), reproducibility, and stability, and it can be used as an alternative system to detect TC from animal-origin food products.

scholarly journals Electroanalytical Performance of a Carbon Paste Electrode Modified by Coffee Husks for the Quantification of Acetaminophen in Quality Control of Commercialized Pharmaceutical Tablets

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Serge Foukmeniok Mbokou ◽  
Maxime Pontié ◽  
Jean-Philippe Bouchara ◽  
Francis Merlin Melataguia Tchieno ◽  
Evangeline Njanja ◽  
...  
Keyword(s):  
Carbon Paste Electrode ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Current Response ◽  
Carbon Paste ◽  
Pharmaceutical Tablets ◽  
Paste Electrode

Electrochemical determination of acetaminophen (APAP) was successfully performed using a carbon paste electrode (CPE) modified with coffee husks (CH-CPE). Scanning electron microscopy (SEM) and SEM-energy dispersive X-ray spectroscopy (SEM-EDX) were, respectively, used for the morphological and elemental characterization of coffee husks prior to their utilization. The electrochemical oxidation of APAP was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV). SWV technique appeared to be more sensitive since the oxidation current of APAP was twofold higher with the CH-CPE sensor than with the bare CPE, in relation to the increase in the organophilic character of the electrode surface. Furthermore, on CH-CPE, the current response of APAP varied linearly with its concentration in the range of 6.6 μM to 0.5 mM, leading to a detection limit of 0.66 μM (S/N=3). Finally, the proposed CH-CPE sensor was successfully used to determine the amount of APAP in commercialized tablets (Doliprane® 500 and Doliprane 1000), with a recovery rate ranging from 98% to 103%. This novel sensor opens the way for the development of low-cost and reliable devices for the electroanalysis of pharmaceutical formulations in developing countries.

scholarly journals A Sensitive Aptamer-Based Biosensor for Electrochemical Quantification of PSA as a Specific Diagnostic Marker of Prostate Cancer

2020 ◽  
Vol 23 ◽  
pp. 243-258 ◽  
Author(s):  
Shokoufeh Hassani ◽  
Armin Salek Maghsoudi ◽  
Milad Rezaei Akmal ◽  
Soheila Rahmani Rahmani ◽  
Pouria Sarihi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Specific Antigen ◽  
Differential Pulse ◽  
Label Free ◽  
Serum Samples ◽  
Highly Sensitive ◽  
Set Up

Purpose: The current project aimed to design a simple, highly sensitive, and economical label-free electrochemical aptasensor for determination of prostate-specific antigen (PSA), as the gold standard biomarker for prostate cancer diagnosis. The aptasensor was set up using a screen-printed carbon electrode (SPCE) modified by gold nanoparticles (Au NPs) conjugated to thiolated aptamers. Methods: Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented for electrochemical (EC) characterization of the aptasensor. The determination of PSA was also performed through differential pulse voltammetry (DPV) in [Fe (CN) 6]3-/4- electrolyte solution. Results: The present aptasensor was shown an outstanding linear response in the concentration range of 1 pg/mL - 200 ng/mL with a remarkably lower limit of detection of 0.077 pg/mL. The optimum concentration for PSA separation and the optimum incubation time for antigen-aptamer binding were determined by observing and electing the highest electrochemical responses in a specified time or concentration. Conclusion: According to the results of the specificity tests, the designed aptasensor did not show any significant interactions with other analytes in real samples. Clinical functionality of the aptasensor was appraised in serum samples of healthy individuals and patients examining the PSA level through the fabricated aptasensor and the reference methods. Both methods are comparable in sensitivity. The present fabricated PSA aptasensor with substantial characteristics of ultra-sensitivity and cost-effectiveness can be conventionally built and used for the routine check-up of the men for prostate problems.

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