Nanoparticle-modified Screen-printed Carbon Electrode Research Articles

Nickel Tungstate Nanoparticle-Modified Screen-Printed Carbon Electrode: The Disposal Strip for the Electrochemical Detection of Tertiary Butylhydroquinone

Nickel Tungstate Nanoparticle-Modified Screen-Printed Carbon Electrode: The Disposal Strip for the Electrochemical Detection of Tertiary Butylhydroquinone

4-Cyanophenol herbicide sensor using multi-walled carbon nanotube embedded dual-microporous polypyrrole nanoparticles as metal-free and environmentally friendly hybrid electrode.

A highly sensitive 4-cyanophenol (4-CP) sensor was fabricated using multi-walled carbon nanotube (MWCNT)-embedded dual-microporous polypyrrole nanoparticle-modified screen-printed carbon electrodes (SPCE/DMPPy/MWCNT). The well-defined dual pores of DMPPy and MWCNT (~ 0.53 and ~ 0.65nm) acted as good analyte absorption agents (shortening the ion diffusion path) and conducting agents (reducing the internal electron-transfer resistance). This enhanced electrical conductivity resulted in the improved electro-oxidation of 4-CP. A higher sensitivity (19.0 μA μM-1cm-2) and lower limit of detection (0.8nM) were achievedwith a wide detection range of 0.001-400µM (R2 = 0.9988). The proposed sensor exhibited excellent recovery of 4-CP in real-world samples. Therefore, the SPCE/DMPPy/MWCNT sensor is regardedhighly suitable for rapidly detecting 4-CP.

An amperometric electrochemical sensor based on hierarchical dual- microporous structure polypyrrole nanoparticles for determination of pyrogallol in the aquatic environmental samples

Pyrogallol (PY) is commonly found as inherent toxicity of industrial effluents which easily enter to the aquatic environment; owing to its oxygen free radicals which causes several health issues. We report a highly sensitive and selective pyrogallol (PY) sensor using hierarchical dual-microporous polypyrrole nanoparticle-modified screen-printed carbon electrode (MPNPs/SPCE). The proposed electrode material for the cost-effective and rapid estimation of PY in the environmental water samples. Hierarchical dual-microporous polypyrrole nanoparticles were prepared through the simple chemical polymerization of pyrrole using Pluronic F-127 as the surfactant. The MPNPs possess well-defined dual micropore (∼0.52 and ∼ 0.67 nm) and a large BET surface area (183 m2/g). The electro-oxidation behavior of PY was examined by cyclic voltammetry and amperometric technique. Hierarchical structure with dual-microporous networks, and large specific surface area of MPNPs were assumed to be greatly enhanced the adsorption rate and a fast facilitate ion transfer for PY sensor. Owing to the effective coupling of hydrogen bonding (interaction between –OH group of PY and –NH group of polymer chain) and π -π interactions (between PPy rings and the PY aromatic rings) can offer more accessible electrochemical active sites and electrolyte/electrode contact interfaces for rapid electro-oxidation response. As a result, wide linear range (0.05–130 μM), good detection limit (0.03 μM), and high sensitivity (1.213 μA μM−1 cm−2) toward PY surpass those of other modified electrodes. Furthermore, MPNPs/SPCE system exhibited desirable selectivities, good steady stabilities, and reproducibilities as PY sensors. Real domestic, industrial, and sewage environmental water samples were analyzed, with quantification data compared with those obtained by HPLC.

Development of an amperometric sensor based on the synergistic action between alginic acid and nPEDOT on a gold nanoparticle-modified screen–printed carbon electrode for As(III) determination in natural water samples

Development of an amperometric sensor based on the synergistic action between alginic acid and nPEDOT on a gold nanoparticle-modified screen–printed carbon electrode for As(III) determination in natural water samples

Disposable biosensors based on platinum nanoparticle-modified screen-printed carbon electrodes for the determination of biogenic amines

This work presents the development of disposable biosensors used in the determination of biogenic amines. The biosensors were fabricated using diamine oxidase (DAOx) or monoamine oxidase (MAOx) enzyme- and platinum nanoparticle (PtNP)-modified screen-printed carbon electrodes (SPCE). The morphological and electrochemical properties of the biosensors were examined by scanning electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry measurements. Amperometric measurements indicated that the DAOx/PtNP/SPCE biosensor responded to histamine, putrescine, cadaverine, spermine, spermidine, β-phenylethylamine, tryptamine, and tyramine; however, its MAOx-based counterpart showed no response towards putrescine and cadaverine. A performance comparison of two biosensors indicated that the one based on DAOx had a linear concentration range from 5.3 × 10− 7 to 7.2 × 10− 5 M and the other based on MAOx from 3.9 × 10− 7 to 7.6 × 10− 5 M for tyramine. The sensitivities of the DAOx- and MAOx-based biosensors towards tyramine were 24.8 µA mM− 1 and 46.1 µA mM− 1, respectively. The proposed biosensors were tested for analysis of blue cheese sample spiked with known concentration of tyramine for the verification of biosensor applicability for real samples.

Impedimetric DNA E-biosensor for multiplexed sensing of Escherichia coli and its virulent f17 strains.

An impedance-based DNA multiplexed biosensor was designed to simultaneously detect Escherichia coli (yaiO gene) and its virulent f17 variant. The thiolated DNA dual probe was self-assembled onto the surface of the gold nanoparticle-modified screen-printed carbon electrode (AuNPs/SPCE) to recognize selected sequences from yaiO and f17 genes. The optimal conditions to prepare the bioelectrode were determined based on the monitoring of the impedimetric response fitted to an equivalent electrical circuit model. The charge transfer resistance of the bioelectrode increased by recognizing the target DNA sequences. Thelimit ofdetection was0.8fM and 1.0fM for yaiO and f17 target DNA, respectively, and the linearity ranged from 1 × 10-15 to 1 × 10-7M with a linear regression coefficient R ≥ 0.995. The nanodevice provided a novel strategy for simultaneous detection of E. coli and its virulence f17 gene with excellent discrimination with a single-base mismatch, two-base mismatch, and non-complementary sequences. Moreover, genomic DNA extracted from E. coli bacteria isolated from diarrheic camel calves and control animals in Tunisia was successfully detected using the as-prepared biosensor with minimal treatment of the extractedDNA samples.Graphical abstract.

Direct competitive immunosensor for Imidacloprid pesticide detection on gold nanoparticle-modified electrodes

A direct competitive immunosensor for the electrochemical determination of Imidacloprid (IMD) pesticide on gold nanoparticle-modified screen-printed carbon electrodes (AuNP-SPCE) is here reported for the first time. Self-obtained specific monoclonal antibodies are immobilized on the AuNP-SPCE taking advantage of the AuNPs biofunctionalization abilities. In our biosensor design, free IMD in the sample competes with IMD conjugated with horseradish peroxidase (IMD-HRP) for the recognition by the antibodies. After that, 3,3′,5,5′-Tetramethylbenzidine (TMB) is enzymatically oxidized by HRP, followed by the oxidized TMB reduction back at the surface of the SPCE. This process gives an associated catalytic current (analytical signal) that is inversely proportional to the IMD amount. The main parameters affecting the analytical signal have been optimized, reaching a good precision (repeatability with a RSD of 6%), accuracy (relative error of 6%), stability (up to one month), selectivity and an excellent limit of detection (LOD of 22 pmol L−1), below the maximum levels allowed by the legislation, with a wide response range (50–10000 pmol L−1). The detection through antibodies also allows to have an excellent selectivity against other pesticides potentially present in real samples. Low matrix effects were found when analysing IMD in tap water and watermelon samples. The electrochemical immunosensor was also validated with HPLC-MS/MS, the reference method used in official laboratories for IMD analysis, through statistical tests. Our findings make the electrochemical immunosensor as an outstanding method for the rapid and sensitive determination of IMD at the point-of-use.

Nanocarbon material-supported conducting poly(melamine) nanoparticle-modified screen-printed carbon electrodes for highly sensitive determination of nitrofuran drugs by adsorptive stripping voltammetry.

The toxicity of nitrofuran drugs has attracted great attention, and the reported electroanalytical methods suffered limited sensitivity. In this work, a sensitive electrochemical assay in the cathodic region is developed to determine four nitrofuran derivatives, including nitrofurantoin (NFT), nitrofurazone (NFZ), furaltadone (FTD), and furazolidone (FZD). The screen-printed carbon electrode (SPCE) was used as the electrode substrate, and the sensing surface was composed of multi-walled carbon nanotube (MWCNT) and conducting poly(melamine) (PME). The overoxidation-pretreated MWCNTs affect the surface morphology of the electrodeposited PME and, thus, the interaction with nitrofuran drugs. The characteristics of the nanocomposite-modified electrode surfaces were well characterized by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and surface water contact angle experiments. The nanocomposite-modified electrodes exhibited excellent adsorption and electrochemical reduction of nitrofurans by cyclic voltammetry. The proposed assay exhibited a linear range of sub-micro to micro molar concentrations for the four drugs under the optimized differential pulse voltammetric (DPV) technique. The detection limits were found to be in the nanomolar ranges. The developed assay was applied to detect NFT in two real samples, and the results showed good recoveries that ranged from 99.0 to 104.8% and 98.0 to 103.2% for milk and lake water samples, respectively. Graphical abstract ᅟ.

Single-frequency impedance analysis of biofunctionalized dendrimer-encapsulated Pt nanoparticles-modified screen-printed electrode for biomolecular detection

We report the fabrication of polyamidoamine (PAMAM) dendrimer with 128 carboxyl group-encapsulated Pt nanoparticle-modified screen-printed carbon electrode, as an impedimetric biosensor, for the quantitative detection of human cardiac biomarker troponin-I (cTnI). PAMAM-Pt was electrochemically deposited over SPCE and its 128 terminal carboxyl groups were used as anchors for the site-specific biomolecular immobilization of protein antibody, anti-cTnI. The biosensor was characterized by contact angle measurements, transmission electron microscopy, UV-visible spectroscopy, and electrochemical techniques. A single-frequency impedance analysis study was utilized for the biomolecular sensing by monitoring the changes in the phase angle obtained at an optimized frequency resulting from antigen-antibody interactions. An optimized frequency of 100 Hz was obtained at which maximum changes in the phase angle were observed after immunoreactions for a given concentration of analyte. A concentration-dependent increase in the phase angle of the biosensor was observed with increasing cTnI concentration in the range of 1 pg mL−1 to 100 ng mL−1. Based on the concentration response data, the dissociation constant was found to be 0.51 pM reflecting high affinity of biosensor towards cTnI analyte arising due to high anti-cTnI loading with a better probe orientation on the 3-dimensional PAMAM-Pt structure.

Voltammetric determination of the Escherichia coli DNA using a screen-printed carbon electrode modified with polyaniline and gold nanoparticles.

The authors describe an electrochemical assay for fast detection of Escherichia coli (E. coli). It is based on a dual signal amplification strategy and the use of a screen-printed carbon electrode (SPCE) whose surface was modified with a polyaniline (PANI) film and gold nanoparticles (AuNPs) via cyclic voltammetry (CV). In the next step, avidin was covalently immobilized on the PANI/AuNP composite on the SPCE surface. Subsequently, the biotinylated DNA capture probe was immobilized onto the PANI/AuNP/avidin-modified SPCE by biotin-avidin interaction. Then, DNA of E.coli, digoxigenin-labeled DNA detector probe and anti-digoxigenin-labeled horseradish peroxidase (HRP) were placed on the electrode. 3,3',5,5'-Tetramethylbenzidine (TMB) andH2O2 solution were added and the CV electrochemical signal was generated at a potential of -0.1V (vs. Ag/AgCl) and a scan rate 50mV.s-1. The assay can detect 4 × 106 to 4CFU of E. coli without DNA amplification. The biosensor is highly specific over other pathogens including Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, Staphylococcus haemolyticus and Pseudomonas aeruginosa. It can be concluded that this genosensor has an excellent potential for rapid and accurate diagnosis of E.coli inflicted infections. Graphical Abstract Schematic of an electrochemical E. coligenosensor based on sandwich assay on a polyaniline/gold nanoparticle-modified screen printed carbon electrode (SPCE). The biosensor can detect 4 × 106 to 4CFU of E. coli without DNA amplification.

Determination of vanillin by using gold nanoparticle-modified screen-printed carbon electrode modified with graphene quantum dots and Nafion.

A voltammetric analytical assay for the selective quantification of vanillin is described. It is based on the use of a gold nanoparticle-modified screen-printed carbon electrode (SPCE) modified with graphene quantum dots (GQD) in a Nafion matrix. The GQD were synthesized by an acidic thermal method and characterized by UV-Vis, photoluminescence, and FTIR spectroscopy. The modified SPCE displays a strongly enhanced response to vanillin. Linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) were applied to optimize the methods. The analytical assay has linear responses in the 13 to 660μM and 0.66 to 33μM vanillin concentration ranges. The detection limits are 3.9μM and 0.32μM when using LSV and DPV, respectively. The analytical assay is selective and stable. It was applied to the determination of vanillin in several food samples with satisfactory results. Recoveries from spiked samples ranged between 92.1 and 113.0%. Graphical abstract The selective and sensitive quantification of vanillin is carried out by the use of a gold nanoparticle-modified screen-printed carbon electrode modified with graphene quantum dots in a Nafion matrix.

Sensitive Impedimetric Immunoassay of Japanese Encephalitis Virus Based on Enzyme Biocatalyzed Precipitation on a Gold Nanoparticle-modified Screen-printed Carbon Electrode.

A sensitive and disposable electrochemical impedance biosensor to detect Japanese encephalitis virus (JEV) was developed based on a gold nanoparticle (AuNP)-modified screen-printed carbon electrode (SPCE). A biosensor was fabricated through covalent grafting of a mixed self-assembled monolayer on AuNPs with a specific antibody. To detect JEV and achieve signal amplification, the horseradish peroxidase (HRP)-labeled second antibody was linked to the biosensor through a sandwich immunity reaction. HRP was used to catalyze 4-chloro-1-naphthol oxidation to produce an insoluble precipitate, which introduced a barrier to electron transfer on the electrode. Electrochemical impedance spectroscopy (EIS) was used to monitor the precipitation on the electrode. The electron-transfer resistance (Ret) of the biosensor was directly correlated with the concentration of JEV in the solution. Under optimal conditions, the method generated a linear response range between 500 and 5 × 105 pfu mL-1, and the detection limit was 167 pfu mL-1. The biosensor exhibited good selectivity against other viruses.

Electrochemical lectin-based biosensor array for detection and discrimination of carcinoembryonic antigen using dual amplification of gold nanoparticles and horseradish peroxidase

An electrochemical lectin-based biosensor array employing lectin as molecular recognition elements was developed for sensitive detection and discrimination of carcinoembryonic antigen (CEA) based on dual signal amplification of gold nanoparticles and enzymatic catalysis. The electrochemical biosensor was fabricated by self-assembly of cysteamine on the surface of gold nanoparticle-modified screen-printed carbon electrodes and subsequently covalently coupling lectins on the surface of the cysteamine-modified electrode via the amidation reaction. A lectin–target-antibody sandwich-type conjugate was formed when the biosensor was successively reacted with target protein and horseradish peroxidase labeled anti-CEA antibody probe. In the presence of hydroquinone and hydrogen peroxide, the resulted biosensor produced an obvious catalysis current signal. The catalytic current at −0.25V was linear with the concentration of CEA in the range of 1ng/mL to 10ng/mL with detection limit of 0.03ng/mL and 0.05ng/mL using concanavalin A and wheat-germ agglutinin as molecular recognition element, respectively, and in the range of 0.5ng/mL to 7ng/mL with detection limit of 0.01ng/mL using Lens culinaris agglutinin as molecular recognition element. Additionally, the lectin-based biosensor array was successfully applied to evaluate the glycan expression of CEA N-glycan and discriminate CEA between healthy and cancer serum samples. The lectin-based biosensor array endows a feasibility tool for clinical diagnosis in complex biological systems and shows great promise for cancer detection and further pathological study of carcinogenesis.

Detection of Cryptosporidium parvum Oocysts on Fresh Produce Using DNA Aptamers.

There are currently no standard methods for the detection of Cryptosporidium spp., or other protozoan parasites, in foods, and existing methods are often inadequate, with low and variable recovery efficiencies. Food testing is difficult due to the low concentrations of parasites, the difficulty in eluting parasites from some foods, the lack of enrichment methods, and the presence of PCR inhibitors. The main objectives of the present study were to obtain DNA aptamers binding to the oocyst wall of C. parvum, and to use the aptamers to detect the presence of this parasite in foods. DNA aptamers were selected against C. parvum oocysts using SELEX (Systematic Evolution of Ligands by EXponential enrichment). Ten rounds of selection led to the discovery of 14 aptamer clones with high affinities for C. parvum oocysts. For detecting parasite-bound aptamers, a simple electrochemical sensor was employed, which used a gold nanoparticle-modified screen-printed carbon electrode. This aptasensor was fabricated by self-assembling a hybrid of a thiolated ssDNA primer and the anti- C. parvum aptamer. Square wave voltammetry was employed to quantitate C. parvum in the range of 150 to 800 oocysts, with a detection limit of approximately 100 oocysts. The high sensitivity and specificity of the developed aptasensor suggests that this novel method is very promising for the detection and identification of C. parvum oocysts on spiked fresh fruits, as compared to conventional methods such as microscopy and PCR.

Detection of the peanut allergen Ara h 6 in foodstuffs using a voltammetric biosensing approach.

A voltammetric biosensor for Ara h 6 (a peanut allergen) detection in food samples was developed. Gold nanoparticle-modified screen-printed carbon electrodes were used to develop a sandwich-type immunoassay using two-monoclonal antibodies. The antibody-antigen interaction was detected through the electrochemical detection of enzymatically deposited silver. The immunosensor presented a linear range between 1 and 100 ng/ml, as well as high precision (inter-day RSD ≤9.8%) and accuracy (recoveries ≥96.7%). The detection and quantification limits were 0.27 and 0.88 ng/ml, respectively. It was possible to detect small levels of Ara h 6 in complex food matrices.

Hollow fiber solid phase microextraction coupled to square wave anodic stripping voltammetry for selective preconcentration and determination of trace levels of mercury in liquid fuel samples

A sensitive, selective and reproducible method for quantification of mercury in gasoline and diesel samples has been developed. The procedure is based on the retention of Hg(II) in hollow fiber-supported sol–gel combined with Ambersep GT74 cation exchange resin. The retained Hg(II) was determined by square wave anodic stripping voltammetry (SQWASV) at gold nanoparticle-modified screen printed carbon electrodes (AuNPs-SPCEs). The optimization of different experimental parameters affecting the hollow fiber solid phase microextraction (HF-SPME) coupled to SQWASV (HF-SPME-SQWASV) procedure was performed using multivariate strategy. Under optimized conditions, a preconcentration factor of 854 was achieved. The repeatability (n = 20) and reproducibility (n = 10) expressed in terms of relative standard deviation (%RSD) were <3 and 5.3 %, respectively. The limits of detection and quantification in the original sample, were 1.0 and 3.0 ng L−1, respectively. The accuracy of the developed HF-SPME-SQWASV method was tested by the analysis of spiked samples and the recovery percentages ranged from 96 to 100 %. The proposed method was applied for quantification of Hg(II) in commercial gasoline and diesel samples. The concentrations of Hg determined using the developed method was compared with those obtained using ICP-MS after microwave-assisted digestion. According to the Student t test, the results obtained were in close agreement (not significantly different at 95 % confidence level).

A Novel Real-Time, Mediator-Free, Non-Enzymatic Electrochemical Biosensor for Glutamate Detection

Glutamate is the major excitatory neurotransmitter in the brain, and an excess of glutamate can cause excitotoxicity, which is a common pathological process in many neurologic disorder such as stroke, brain trauma, and brain tumor. Therefore, monitoring glutamate in real time is of critical importance. However, the existing methods for the detection and monitoring glutamate levels are limited. Here in this work, we present a novel mediator-free, non-enzymatic electrochemical biosensor for real-time glutamate monitoring, based on immobilization of genetically engineered periplasmic glutamate binding protein onto gold nanoparticle-modified screen-printed carbon electrodes. Cyclic voltammetry is performed to determine the glutamate concentration in phosphate buffer solution (pH=7.4). The results show an excellent sensitivity with 0.1µM detection limit and the linearity was investigated in the 0.1µM-1µM range of glutamate concentration. The sensor was tested with common interfering substances such as aspartate, glutamine, serine, lysine and ascorbic acid, and exhibited high selectivity toward glutamate over those substances. Figure 1

A disposable label-free electrochemiluminescent immunosensor for transferrin detection based on a luminol-reduced gold nanoparticle-modified screen-printed carbon electrode

A disposable label-free electrochemiluminescent immunosensor based on luminol-reduced gold nanoparticles was designed for human transferrin detection.

Ultrasensitive norovirus detection using DNA aptasensor technology.

DNA aptamers were developed against murine norovirus (MNV) using SELEX (Systematic Evolution of Ligands by EXponential enrichment). Nine rounds of SELEX led to the discovery of AG3, a promising aptamer with very high affinity for MNV as well as for lab-synthesized capsids of a common human norovirus (HuNoV) outbreak strain (GII.3). Using fluorescence anisotropy, AG3 was found to bind with MNV with affinity in the low picomolar range. The aptamer could cross-react with HuNoV though it was selected against MNV. As compared to a non-specific DNA control sequence, the norovirus-binding affinity of AG3 was about a million-fold higher. In further tests, the aptamer also showed nearly a million-fold higher affinity for the noroviruses than for the feline calicivirus (FCV), a virus similar in size and structure to noroviruses. AG3 was incorporated into a simple electrochemical sensor using a gold nanoparticle-modified screen-printed carbon electrode (GNPs-SPCE). The aptasensor could detect MNV with a limit of detection of approximately 180 virus particles, for possible on-site applications. The lead aptamer candidate and the aptasensor platform show promise for the rapid detection and identification of noroviruses in environmental and clinical samples.

Rapid Quantitative Detection of Brucella melitensis by a Label-Free Impedance Immunosensor Based on a Gold Nanoparticle-Modified Screen-Printed Carbon Electrode

A rapid and simple method for quantitative monitoring of Brucella melitensis using electrochemical impedance spectroscopy (EIS) is reported for the first time. The label-free immunosensors were fabricated by immobilizing Brucella melitensis antibody on the surface of gold nanoparticle-modified screen-printed carbon electrodes (GNP-SPCEs). Cyclic voltammetry (CV) and EIS were used to characterize the Brucella melitensis antigen interaction on the surface of GNP-SPCEs with antibody. A general electronic equivalent model of an electrochemical cell was introduced for interpretation of the impedance components of the system. The results showed that the change in electron-transfer resistance (Rct) was significantly different due to the binding of Brucella melitensis cells. A linear relationship between the Rct variation and logarithmic value of the cell concentration was found from 4 × 104 to 4 × 106 CFU/mL in pure culture. The label-free impedance biosensor was able to detect as low as 1 × 104 and 4 × 105 CFU/mL of Brucella melitensis in pure culture and milk samples, respectively, in less than 1.5 h. Moreover, a good selectivity versus Escherichia coli O157:H7 and Staphylococcus aureus cells was obtained for our developed immunosensor demonstrating its specificity towards only Brucella melitensis.