Modification Of Screen-printed Carbon Electrode Research Articles

Surface Modification of Screen-Printed Carbon Electrode through Oxygen Plasma to Enhance Biosensor Sensitivity.

The screen-printed carbon electrode (SPCE) is a useful technology that has been widely used in the practical application of biosensors oriented to point-of-care testing (POCT) due to its characteristics of cost-effectiveness, disposability, miniaturization, wide potential window, and simple electrode design. Compared with gold or platinum electrodes, surface modification is difficult because the carbon surface is chemically or physically stable. Oxygen plasma (O2) can easily produce carboxyl groups on the carbon surface, which act as scaffolds for covalent bonds. However, the effect of O2-plasma treatment on electrode performance remains to be investigated from an electrochemical perspective, and sensor performance can be improved by clarifying the surface conditions of plasma-treated biosensors. In this research, we compared antibody modification by plasma treatment and physical adsorption, using our novel immunosensor based on gold nanoparticles (AuNPs). Consequently, the O2-plasma treatment produced carboxyl groups on the electrode surface that changed the electrochemical properties owing to electrostatic interactions. In this study, we compared the following four cases of SPCE modification: O2-plasma-treated electrode/covalent-bonded antibody (a); O2-plasma-treated electrode/physical adsorbed antibody (b); bare electrode/covalent-bonded antibody (c); and bare electrode/physical absorbed antibody (d). The limits of detection (LOD) were 0.50 ng/mL (a), 9.7 ng/mL (b), 0.54 ng/mL (c), and 1.2 ng/mL (d). The slopes of the linear response range were 0.039, 0.029, 0.014, and 0.022. The LOD of (a) was 2.4 times higher than the conventional condition (d), The slope of (a) showed higher sensitivity than other cases (b~d). This is because the plasma treatment generated many carboxyl groups and increased the number of antibody adsorption sites. In summary, the O2-plasma treatment was found to modify the electrode surface conditions and improve the amount of antibody modifications. In the future, O2-plasma treatment could be used as a simple method for modifying various molecular recognition elements on printed carbon electrodes.

A disposable sensor based on one-pot synthesized tungsten oxide nanostructure-modified screen printed electrodes for selective detection of dopamine and uric acid.

Here, screen-printed carbon electrodes (SPCEs) were modified with ultrafine and mainly mono-disperse sea urchin-like tungsten oxide (SUWO3) nanostructures synthesized by a simple one-pot hydrothermal method for non-enzymatic detection of dopamine (DA) and uric acid (UA) in synthetic urine. Sea urchin-like nanostructures were clearly observed in scanning electron microscope images and WO3 composition was confirmed with XRD, Raman,FTIR and UV-Vis spectrophotometer. Modification of SPCEs with SUWO3 nanostructures via the drop-casting method clearly reduced the Rct value of the electrodes, lowered the ∆Ep and enhanced the DA oxidation current due to high electrocatalytic activity. As a result, SUWO3/SPCEs enabled highly sensitive non-enzymatic detection of DA (LOD: 51.4nM and sensitivity: 127µAmM-1cm-2) and UA (LOD: 253nM and sensitivity: 55.9µAmM-1cm-2) at low concentration. Lastly, SUWO3/SPCEs were tested with synthetic urine, in which acceptable recoveries for both molecules (94.02-105.8%) were obtained. Given the high selectivity, the sensor has the potential to be used for highly sensitive simultaneous detection of DA and UA in real biological samples.

Modification of Screen-printed Carbon Electrodes with Gold Particles to Enhance Luminol Electrochemiluminescence for Hydrogen Peroxide Detection

Modification of Screen-printed Carbon Electrodes with Gold Particles to Enhance Luminol Electrochemiluminescence for Hydrogen Peroxide Detection

Novel Sensitive Electrochemical Immunosensor Development for the Selective Detection of HopQ H. pylori Bacteria Biomarker.

Helicobacter pylori (H. pylori) is a highly contagious pathogenic bacterium that can cause gastrointestinal ulcers and may gradually lead to gastric cancer. H. pylori expresses the outer membrane HopQ protein at the earliest stages of infection. Therefore, HopQ is a highly reliable candidate as a biomarker for H. pylori detection in saliva samples. In this work, an H. pylori immunosensor is based on detecting HopQ as an H. pylori biomarker in saliva. The immunosensor was developed by surface modification of screen-printed carbon electrodes (SPCE) with MWCNT-COOH decorated with gold nanoparticles (AuNP) followed by HopQ capture antibody grafting on SPCE/MWCNT/AuNP surface using EDC/S-NHS chemistry. The sensor performance was investigated utilizing various methods, such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX). H. pylori detection performance in spiked saliva samples was evaluated by square wave voltammetry (SWV). The sensor is suitable for HopQ detection with excellent sensitivity and linearity in the 10 pg/mL-100 ng/mL range, with a 2.0 pg/mL limit of detection (LOD) and an 8.6 pg/mL limit of quantification (LOQ). The sensor was tested in saliva at 10 ng/mL, and recovery of 107.6% was obtained by SWV. From Hill's model, the dissociation constant Kd for HopQ/HopQ antibody interaction is estimated to be 4.60 × 10-10 mg/mL. The fabricated platform shows high selectivity, good stability, reproducibility, and cost-effectiveness for H. pylori early detection due to the proper choice of biomarker, the nanocomposite material utilization to boost the SPCE electrical performance, and the intrinsic selectivity of the antibody-antigen approach. Additionally, we provide insight into possible future aspects that researchers are recommended to focus on.

Cyclic Voltammetry of Screen-Printed Carbon Electrode Coated with Ag-ZnO Nanoparticles in Chitosan Matrix.

In this paper, the authors describe the fabrication of nanocomposite chitosan-based systems of zinc oxide (ZnO), silver (Ag) and Ag-ZnO. Recently, the development of coated screen-printed electrodes using metal and metal oxide nanoparticles (NPs) for the specific detection and monitoring of different cancer tumors has been obtaining important results. Ag, ZnO NPs and Ag-ZnO prepared by the hydrolysis of zinc acetate blended with a chitosan (CS) matrix were used for the surface modification of screen-printed carbon electrodes (SPCEs) in order to analyze the electrochemical behavior of the typical redox system of a 10 mM potassium ferrocyanide-0.1 M buffer solution (BS). The solutions of CS, ZnO/CS, Ag/CS and Ag-ZnO/CS were prepared in order to modify the carbon electrode surface, and were measured at different scan rates from 0.02 V/s to 0.7 V/s by cyclic voltammetry. The cyclic voltammetry (CV) was performed on a house-built potentiostat (HBP). The cyclic voltammetry of the measured electrodes showed the influence of varying the scan rate. The variation of the scan rate has an influence on the intensity of the anodic and cathodic peak. Both values of currents (anodic and cathodic currents) have higher values for 0.1 V/s (Ia = 22 μA and Ic = -25 μA) compared to the values for 0.06 V/s (Ia = 10 μA and Ic = -14 μA). The CS, ZnO/CS, Ag/CS and Ag-ZnO/CS solutions were characterized using a field emission scanning electron microscopy (FE-SEM) with EDX elemental analysis. The modified coated surfaces of screen-printed electrodes were analyzed using optical microscopy (OM). The present coated carbon electrodes showed a different waveform compared to the voltage applied to the working electrode, depending on the scan rate and chemical composition of the modified electrodes.

Picosecond laser-assisted synthesis of silver nanoparticles with high practical application as electroanalytical sensor

Gallic acid (GA) is one of the most important and present natural phenolic compounds due to its well-known biological properties, and its detection and monitoring is of great importance. Silver nanoparticles (AgNPs) are one of the most studied metallic nanomaterials used in various fields, from biomedical applications to electrochemical sensing devices. In this work, we used the pulsed laser ablation technique in liquid for the one-step preparation of nanoparticles of silver from a pure silver plate base in N,N-dimethylformamide. Obtained nanomaterial was characterized using morphological and electrochemical methods and used for modification of screen-printed carbon electrodes (SPCE). Successful immobilization at the surface is confirmed using the surface profiling method. A newly obtained sensor was used for the detection of GA. After parameters optimization, a differential pulse voltammetric protocol was developed, using two approaches - concentration vs. current (GA determination) and peak area vs. current (estimation of the antioxidant capacity). For the first approach sensor linearity was found to be in the range from 0.50 µM to 10 µM, with the limit of detection (LOD) of 0.16 µM and limit of quantification (LOQ) of 0.50 µM. In the second system operating linear range was the same, while LOD and LOQ were 0.11 µM and 0.34 µM, respectively. Practical application of the method was tested using two approaches: direct measurement of gallic acid in biological fluids and estimation of the antioxidant capacity and food quality purpose.

The development of disposable electrochemical sensor based on MoSe2-rGO nanocomposite modified screen printed carbon electrode for amitriptyline determination in the presence of carbamazepine, application in biological and water samples

The present attempt developed a simple sensing system based on the modification of screen-printed carbon electrode (SPCE) with MoSe2/reduced graphene oxide (rGO) nanocomposite (MoSe2-rGO/SPCE) to voltammetrically co-detect amitriptyline and carbamazepine. Different techniques such as field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize MoSe2-rGO nanocomposite morphology and structure. Moreover, chronoamperometry, differential pulse voltammetry (DPV) and linear sweep voltammetry (LSV) were utilized to explore the electrochemical oxidation of amitriptyline. Data revealed a great current sensitivity for the MoSe2-rGO/SPCE towards amitriptyline. The peak currents of amitriptyline oxidation on the MoSe2-rGO/SPCE had linear dynamic range (0.02–380.0 μM) and a narrow limit of detection (0.007 μM). The MoSe2-rGO/SPCE was successful in sensing carbamazepine and amitriptyline in real specimens, with appreciable recovery rates.

Modification of screen-printed carbon electrode (SPCE) by the Nafion functionalized silicon nanoparticles (SiNP/Naf) materials in non-enzymatic electrochemical sensor for uric acid (UA) detection

A non-enzymatic electrochemical sensor has been successfully developed to detect uric acid (UA) based on a modified screen-printed carbon electrode (SPCE) using Nafion functionalized silicon nanoparticles. Silicon nanoparticles (SiNPs) material is used because of their advantages, including its abundant availability, good biocompatibility, and adjustable porosity and surface area according to the synthesis method used. Nafion is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer that has been widely used for electrochemical sensors and is functioned as a stabilizer of the sensor. In this study, SiNPs material was successfully synthesized through the non-thermal chemical vapor deposition method. XRD diffractogram and SEM image confirmed its structure and morphology. The crystallinity of the produced SiNPs is 69.85%. SEM-EDS characterization was also carried out to confirm the success of the SPCE modification by SiNPs and SiNPs/Naf materials. The changes in the morphology of SPCE and the EDS spectrum that were measured indicated the success of the SPCE modification process for each stage. Cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry study were used to analyze the electrochemical characteristics and performance of non-enzymatic electrochemical sensors based on SPCE/SiNPs/Naf structures against uric acid analytes. Based on the results of electrochemical analysis, the sensitivity, detection limit, and quantification limit of the sensor are 0.01 μA.mM-1. cm-2, 0.21 μM, and 0.69 μM respectively in the linear measurement range of uric acid concentration of 10 – 1000 μM. Then, a sensor stability study was also carried out which resulted in an RSD value of 4.83%.

Surface oxygen plasma modification of screen-printed carbon electrode for quantitative determination of sunset yellow and tartrazine in foods

Surface oxygen plasma modification of screen-printed carbon electrode for quantitative determination of sunset yellow and tartrazine in foods

Graphene oxide modified screen-printed electrode for highly sensitive and selective electrochemical detection of ciprofloxacin residues in milk

The monitoring of antibiotic residues in foodstuffs by using rapid detection method is essential for food safety. In this work, the electrochemical sensor was developed by modification of screen-printed carbon electrode with graphene oxide, and then the ciprofloxacin (CIP) was detected based on the complexation of CIP with Mn2+. On modified electrode, the anodic stripping peak current response of Mn2+ was prohibited in the presence of CIP, and a peak current response of the complex was occurred. Thus, the peak current response of the complexation peak was employed as the indicating signal for CIP determination, which was more sensitive than the direct electrochemical oxidation response of CIP. Parameters that affect the signal response have been investigated in method. Under the optimum conditions, the peak current of the complexation peak was linearly correlated with the CIP content in the milk sample solution at 1.0 to 8.0 μM, and the linear correlation coefficients (R2) was 0.994. The limits of detection (LOD) was 0.30 μM. Recoveries of CIP in milk sample were ranged from 81.0 to 95.4% with relative standard deviations (RSDs) below 4.6%. The method showed high selectivity and sensitive, good reproducibility, indicated that this method has potential to be applied in CIP residue analysis.

Pd–Au Heteropentamers: Selective Growth of Au on Pd Tetrahedral Nanoparticles with Enhanced Electrocatalytic Activity

We developed a seed-mediated approach for the selective growth of Au-on-Pd tetrahedral nanoparticles giving rise to Pd–Au heteropentamers. The size of the Au domains in the heterostructures could be finely tuned from 5 to 8 nm. High-resolution transmission electron microscopy characterization demonstrated that the heteromers are single crystalline indicating an epitaxial growth of Au on Pd. The modification of screen-printed carbon electrodes with Pd–Au heteromers shows an improved electrocatalytic activity.

A single drop histamine sensor based on AuNPs/MnO2 modified screen-printed electrode

In order to ensure high food quality, one of the prime importance is the detection and quantification of histamine, well known marine food poison. In this work, we constructed novel electrochemical biosensor for the detection of histamine based on gold nanoparticles decorated on manganese dioxide (Au/MnO2) and used for modification of screen-printed carbon electrode (Au/MnO2@SPCE). The constructed sensor was then used for the estimation of histamine content in a single drop. Materials used in this study were synthesized and characterized using HR-TEM, XRPD and electrochemical methods. The amperometric detection method was optimized and, under selected operating parameters (supporting electrolyte pH 6, working potential of 1 V), the proposed sensor possesses linear working range from 0.3 µM to 5.1 µM, with a detection limit of 0.08 µM. The effect of selected interferences was investigated and it was found that the developed approach offers accurate, precise, selective, fast and reproducible quantification of histamine using only one drop of the sample. In the end, this work stands as a proof-of-concept of the modified electrodes and electrochemical detection as a promising and prospective approach for the applications in real-time monitoring of the food quality.

Tailoring IONP shape and designing nanocomposite IONS@GN toward modification of SPCE to enhance electrochemical degradation of organic dye

Iron oxide nanoparticles (IONP) with different distinctive morphologies (spherical, cubic, flower-like and needles) were utilized for modification of screen-printed carbon electrodes (SPCE) to be used for synthetic organic dye degradation by an electrochemical approach. This platform was implemented for removal of the synthetic organic dye, Reactive Black 5 (RB5) in aqueous solution. Modified SPCE with spherically shaped IONP (IONS) had the highest dye removal efficiency. Thus, IONS were then used for surface decoration of the most common carbon-based materials (graphene, graphene oxide, carboxylated graphene, graphene nanoribbons, graphene nanoplatelets, single- and multi-wall carbon nanotubes), and the nanocomposites formed were deposited on the electrode surfaces. Using IONS/graphene composite (IONS@GN) for electrode modification resulted in the best effect. Removal of RB5 with this electrode was 51% better in comparison with bare SPCE, reducing the time required for complete dye degradation from 61 to 30 min Using IONS-modified SPCE, total RB5 removal occurred in 51 min, improving the performance by 16% over that of bare SPCE. The effects determined, i.e., the best IONP morphology and best type of carbon-based material for nanocomposite formation to enhance RB5 removal will provide guidelines for further modifications of SPCE with nanomaterials and nanocomposites, for application of this electrochemical approach in the degradation of organic pollutants.

Screen-Printed Carbon Electrodes Modified with Graphene Oxide for the Design of a Reagent-Free NAD+-Dependent Biosensor Array.

A facile approach for the construction of reagent-free electrochemical dehydrogenase-based biosensors is presented. Enzymes and cofactors (NAD+ and Fe(CN)63-) were immobilized by modification of screen-printed carbon electrodes with graphene oxide (GO) and an additional layer of cellulose acetate. The sensor system was exemplarily optimized for an l-lactate electrode in terms of GO concentration, working potential, and pH value. The biosensor exhibited best characteristics at pH 7.5 in 100 mM potassium phosphate buffer at an applied potential of +0.250 V versus an internal pseudo Ag reference electrode. Thereby, sensor performance was characterized by a linear working range from 0.25 to 4 mM and a sensitivity of 0.14 μA mM-1. The detection principle was additionally evaluated with three other dehydrogenases (d-lactate dehydrogenase, alcohol dehydrogenase, and formate dehydrogenase, respectively). The developed reagentless biosensor array enabled simultaneous and cross-talk free determination of l-lactate, d-lactate, ethanol, and formate.

Influence of a polymer membrane on the electrochemical determination of insulin in nanomodified screen printed carbon electrodes

Diabetes mellitus can be considered one of the most widespread diseases globally. Hence, the diabetes research is currently focused on developing an effective, low-cost sensor having high stability and suitable analytical characteristics. Screen printed carbon electrodes (SPCEs) embody ideal candidates for insulin determination due to the small area of the working electrode eliminating the solution volume required for the given purpose. Modification of SPCEs by using nanoparticles resulted in an increase of the working electrode surface area and formation of a higher number of active species. The aim of this paper is to examine the impact of a chitosan membrane on the electrochemical determination of insulin on NiO nanoparticles (NiONPs) and multi-walled nanotube (MWCNTs) modified SPCE (NiONPs/MWCNTs/SPCE). This study is primarily conceived to compare the analytical characteristics and stability of NiONPs/chitosan-MWCNTs/SPCE and NiONPs/MWCNTs/SPCE. An electrode modified with chitosan displays a wider linear range, one of 0.25 μM - 5 μM (R2 0.997); a lower limit of detection, 94 nM; a high sensitivity (0.021 μA/μM) and better stability than that of an electrode without chitosan. According to these characteristics, the polymer is considered a necessary compound of the electrochemical insulin sensor, improving the sensor's analytical characteristics.

Surface Modification of Screen-Printed Carbon Electrode (SPCE) with Calixarene-Functionalized Electrochemically Reduced Graphene Oxide (ERGO/C4) in the Electrochemical Detection of Anthracene

In this study, electrochemically reduced graphene oxide (ERGO) and 4-tertbutylcalix[4]arene (C4) were deposited on the surface of screen-printed carbon electrodes (SPCE) to detect anthracene in aqueous solution. The formation of electrochemically reduced graphene oxide/calix[4]arene (ERGO/C4) on SPCE was characterized using Raman spectroscopy, FTIR, and FESEM. Electrochemical properties of the modified electrode were investigated by means of CV and DPV. The electrochemical response of anthracene was greatly improved on ERGO/C4-SPCE compared to bare SPCE. Under optimized condition, the anthracene peak showed a good linear relationship at a concentration ranging from 2–8 nM and a detection limit of 0.016 nM. The developed sensor was able to conserve its performance in the presence of various organic compound and inorganic metal ions and also yielded a good comparable result to the conventional method which is HPLC in real sample with acceptable recovery of 96–97%; thus proving to be a promising candidate for rapid, inexpensive, and sensitive determination of anthracene in real samples.

An electrochemical sensing platform for sensitive detection DNA methylation using Fe3O4/TMC/Au nanocomposite and poly(l-arginine)/reduced graphene oxide modified screen-printed carbon electrode

Objectives: In this study, a simple electrochemical nano-genosensor has been developed for the rapid and sensitive detection of methylated SEPT9 DNA as a useful biomarker for early colorectal cancer detection or screening. Methods: The process consists of three main steps: (i) the surface modification of screen-printed carbon electrode (SPCEs) with a poly(l-Arg)/RGO composite film followed by immobilizing anti-5-methylcytosine antibody (ii) preparation of probe-modified Fe3O4/TMC/Au nanocomposites for the hybridization with complementary DNA sequences, (iii) capturing methylated DNA target by antibody-modified SPCEs and subsequent electrochemical detection through redox peak currents of gold nanoparticles which generated a concentration-dependent response. Results: The surface modification of the electrode and hybridization with the methylated target were confirmed by cyclic voltammetry (CV) method and differential pulse voltammetry (DPV) was employ for quantitative evaluation of methylated target DNA. Conclusion: The assay showed a wide linear range from 0.01 pM to 1000 pM with a low detection limit of 0.01pM.

Development of Highly Sensitive Immunosensor for Clenbuterol Detection by Using Poly(3,4-ethylenedioxythiophene)/Graphene Oxide Modified Screen-Printed Carbon Electrode.

Clenbuterol (CLB) is an antibiotic and illegal growth promoter drug that has a long half-life and easily remains as residue and contaminates the animal-based food product that leads to various health problems. In this work, electrochemical immunosensor based on poly(3,4-ethylenedioxythiophene)/graphene oxide (PEDOT/GO) modified screen-printed carbon electrode (SPCE) for CLB detection was developed for antibiotic monitoring in a food product. The modification of SPCE with PEDOT/GO as a sensor platform was performed through electropolymerization, while the electrochemical assay was accomplished while using direct competitive format in which the free CLB and clenbuterol-horseradish peroxidase (CLB-HRP) in the solution will compete to form binding with the polyclonal anti-clenbuterol antibody (Ab) immobilized onto the modified electrode surface. A linear standard CLB calibration curve with R2 = 0.9619 and low limit of detection (0.196 ng mL−1) was reported. Analysis of milk samples indicated that this immunosensor was able to detect CLB in real samples and the results that were obtained were comparable with enzyme-linked immunosorbent assays (ELISA).

Electroanalytical Application of Screen-printed Carbon Electrode Modified with Conductive Graphene Oxide–Poly(acrylic acid) Film for Label-free Detection of Human Immunoglobulin G

A facile and cost-effective modification of screen-printed carbon electrode employing a graphene oxide–poly(acrylic acid) film allows both good electrochemical reactivity and electrode surface functionalization with antibody. The analytical performances of the modified electrode for detection of human immunoglobulin G (IgG) were satisfied with a linear concentration range of 1.0–100 ng mL−1, sensitivity of 1.2318 µA cm−2 mL ng−1, and a limit of detection of 0.54 ng mL−1. The proposed electrode is promising in sensitive and selective clinical analysis to detect IgG at physiological concentration.

Electrochemical Detection of Human Interleukin-15 using a Graphene Oxide-Modified Screen-Printed Carbon Electrode

ABSTRACTBiofunctionalizing a simple and disposable graphene oxide-modified screen-printed carbon electrode with anti-interleukin-15 antibodies has been successfully demonstrated for the first time for the label-free electrochemical detection of interleukin-15, a biomarker of early HIV infection. To improve the electrochemical reactivity and introduce carboxylic groups on the surface of screen-printed carbon electrode, high-quality graphene oxide was used for the modification of screen-printed carbon electrode. With simple modification of the screen-printed carbon electrode, the device exhibited satisfactory sensitivity, selectivity, stability, reproducibility, and regenerability. The immunosensor provided a detection limit of 3.51 ng mL−1 and a sensitivity of 0.5655 µA cm−2 mL ng−1. The simply constructed immunosensor thus rendered promising device for immunoreactions on the surface of the electrode.